Anton van Leeuwenhoek used a microscope to observe
tiny creatures swimming in a drop of pond water.
How did his observations contribute to the cell theory?
A. He showed that living cells come from other living cells.
B. He was the first person to observe and identify living cells.
C. He was the first person to observe dead plant cells.
D. He showed that all plants and animals are made of cells.

Answers

Answer 1
B. He was the first person to observe and identify living cells.
Answer 2

Answer:

b

Explanation:


Related Questions

What is the difference between a theory and a law in science

Answers

A theory is something that has been proven a few times, so yes it’s been consistent in science but not enough. A law is something multiple scientists have proven to be true multiple times, causing it to be a law.

Which set of atoms are isotopes?
A. 16^ 8X and 16^ 6X
B. 16^ 8X and 17^ 8X
C. 12^ 6X and 14^ 7X
D. 6^ 26X and 26^ 6X

Answers

Answer:

Option B.

Explanation:

Isotopy is a phenomenon where by two or more atoms have the same atomic number (proton) but different mass number due to the difference in neutron present in the atoms. The atoms that exhibit Isotopy are isotopes.

With the above information, we can obtain the right answer to the question given above as follow:

For option A:

Isotope >> atomic no >> Mass no

16 8X >>> 8 >>>>>>>>> 16

16 6X >>> 6 >>>>>>>>> 16

Since they have the different atomic number, they are not isotope.

For option B:

Isotope >> atomic no >> Mass no

16 8X >>> 8 >>>>>>>>> 16

17 8X >>> 8 >>>>>>>>> 17

Since they have the same atomic number but different mass number, they are isotope.

For option C:

Isotope >> atomic no >> Mass no

12 6X >>> 6 >>>>>>>>> 12

14 7X >>> 7 >>>>>>>>> 14

Since they have different atomic number, they are not isotope.

For option D:

Isotope >> atomic no >> Mass no

6 26X >> 26 >>>>>>>>> 6

26 6X >>> 6 >>>>>>>>> 26

Since they have different atomic number, they are not isotope.

From the above illustration, only option B contains isotopes because the atoms have the same atomic number but different mass number

What problem did the development of the metric system solve?

Answers

Answer:

The problems solved by the metric system includes, the eradication of fraud prevalent by the use of the approximately 800 units that were defined in 250 thousand ways due to the difference of the associated quantity to the units in different towns

The development of the metric system also solved the issues scientist had with working with the medieval system which were mainly national and regional systems that hindered scientific communication across regions

Explanation:

1. Isotopes of are atoms of the same element that vary in
A. protons
B. neutrons
C. protons and neutrons
D. neutrons and mass

2. What do these 2 atoms have in common? B-10 and B-11?
A. both have same number of neutrons
B. both have 5 electrons
C. both have 6 protons
D. both have same mass

Explain how you got your answer

Answers

Answer:

1. D

2. B

Explanation:

1. Isotopes vary in neutrons. Due to this variance, the difference in neutrons change the mass of the element.

Note: the amount of protons in an element never changes. The number of protons (the atomic number on the periodic table) identifies the element in question. If you add or subtract protons, you change the element.

2. B-10 and B-11 are two isotopes of the element Boron: One with 10 neutrons, and another with 11 neutrons. Because they contain a variance of neutrons, they do not have the same mass. This cancels choices A and D.

The protons of an element are equal to the atomic number of that element. Borons atomic number is 5 (according to the periodic table), so it contains 5 protons. This cancels choice C as the element with 6 protons is Carbon.

Note: The amount of protons in an atom is balanced out by the same amount of electrons to allow for a neutral charge of the element (i.e., the protons, which contain a positive charge, and electrons, which contain a negative charge, cancel each other out. In the case of Boron: +5 protons - 5 electrons = 0 charge). This is why choice B is correct, as the consideration of an ion is not necessary for this question.

A student needs exactly 1 gram of baking powder to conduct an experiment. The balance reads 0.37 grams. How
much more baking powder does the student need?

A. 50 grams
B. 63 grams
C. 75 grams
D. 36 grams

Answers

Answer:

B

Explanation:

If the student needs one gram but so far only has 0.37 grams, then the amount they need is the difference between what they need and how much they already have. 1-0.37=0.63 grams.

...which isn't actually an option because none of them have decimal points but I would say it is B anyway because it is the equivalent ratio and maybe there was a typo.

Hope this helped!

Answer:

The answer is B :)

Explanation:

explain why the following statement is false: “if a theory is accepted for a long time, it eventually becomes a law.” include specific details about both theories and laws in your explanation.

Answers

Explanation:

hope this will help you

A standard gold bar has a mass of 12.4 kg. When the gold bar is placed into a container of water the volume changes by 642 mL. What is the density of gold in g/mL

Answers

Answer:

19.3 g/mL

Explanation:

The following data were obtained from the question:

Mass (m) = 12.4 kg

Volume (V) = 642 mL.

Density (D) =.?

Next, we shall convert 12.4 kg to grams. This can be obtained as follow:

1 kg = 1000 g

Therefore,

12.4 kg = 12.4 × 1000

12.4 kg = 12400 g

Therefore, 12.4 kg is equivalent to 12400 g.

Finally, we shall determine the density of the gold as follow:

Density is simply defined as the mass of the substance per unit volume of the substance. It can be represented mathematically as:

Density (D) = mass (m) / volume (V)

D = m/V

With the above formula, the density of gold can easily be obtained as follow:

Mass (m) = 12400 g

Volume (V) = 642 mL.

Density (D) =.?

D = m/V

D = 12400/642

D = 19.3 g/mL

Therefore, the density of hold is 19.3 g/mL

An Olympic swimming pool is 50 meters long. You swim from one end to the other four times.How many meters do you swim?

Answers

Answer:

200 meters

Explanation:

if u swim for each end 4 times, and its 50 meters long, 50 x 4 = 200 meters

The answer is 200 because if the pool is 50 meters and you go back and forth 4 times. 50 X 4 = 200.

hydrogen ions cannot exist alone but they exist after combining with water molecules true or false​

Answers

True because hydrogen ions combines with h2o to make hydronium ion, so in a sense h2o is acting like a base.

3. How many protons do the following have?
Calcium
Gold
Copper
Iron

Answers

Answer:

calcium=20

gold=79

copper=29

iron=26

Explanation:

What products are formed when a hydrocarbon combusts?
A. Hydrogen and oxygen
B. Carbon dioxide and water
C. Carbon dioxide and hydrogen
D. Water and hydrogen

Answers

Answer:

b

Explanation:

The products are formed when a hydrocarbon combusts are carbon dioxide and water and the correct option is option B.

Combustion is a chemical reaction that occurs when a fuel combines with an oxidizing agent, typically oxygen, resulting in the release of heat and the formation of products. It is an exothermic reaction, meaning it releases energy in the form of heat and light.

During combustion, the fuel undergoes rapid oxidation, breaking its chemical bonds and forming new bonds with oxygen. Common examples of combustion include burning of wood, gasoline, natural gas, and other hydrocarbon fuels.

The reaction is often accompanied by the production of flames and the release of carbon dioxide and water vapor.

Thus, the ideal selection is option B.

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Can skmebodynheop me with this it’s science.

Answers

Answer:

v=50km/hr

Explanation:

Given:

s= 300km

t= 6 hours

Required:

v=?

Formula:

v=s/t

Solution:

v=s/t

v=300km/6h

v=50km/hr

Hope this helps ;) ❤❤❤

what are electrode potential​

Answers

Answer:

Electrode potential is the electromotive force to the galvanic cell built standard.

Explanation:

Electrode potential is the convention electrode is the standard hydrogen electrode to the value zero potential.

Electrode potential is the origin to the developed in that interface between the electrode and electrolyte.Electrode potential is the interface due to the transfer of across the specific of molecules to the electrode potential.Electrode potential that working potential non zero reaction net current the working electrode potential.Electrode potential is that performed  extrapolation of that measured to that values set that standard.Electrode potential under the depends on the nature of that contacting electrode reactions to the interface.Electrode with hydrogen is that ideal solution is zero potential to the all temperature  to standard formation.Electrode potential to the working electrode, counter electrode and reference electrode that using three setup electrode.Electrode potential are performed the positive of that connected to that working electrode terminal to reference electrode.

Answer:

In electrochemistry, electrode potential is the electromotive force of a galvanic cell built from a standard reference electrode and another electrode to be characterized.

PLEASE HELP ME :( It’s urgent!!!!!

Answers

Answer:

C and D

Explanation:

In the first table, both element particles have more electrons than protons which is unusual and indicates they have a negative charge. Furthermore both numbers add up to full electron shells (2,8 and 2,8,8) meaning they are ions (charged particles formed to gain full valence shells and become stable), so it is C for the first question, negative ions.

As for the second one, isotopes like versions of the same element except with different numbers of neutrons, so they are still the same element but have different mass. As shown here the numbers indicate the number of neutrons therefore it is D, 3 more neutrons and no more electrons.

Hope this helped!

The density of helium is 0.17 g/L. What Is the mass of helium in a 5.4 L helium balloon? (2 sig figs) *

Answers

Answer:

The correct answer is 0.92 g

Explanation:

The density is defined as the mass per unit of volume:

Density= mass/volume

From the data provided:

volume= 5.4 L

density= 0.17 g/L

Thus, to calculate the mass of helium:

mass= density x volume = 0.17 g/L x 5.4 L= 0.918 g ≅ 0.92 g

A 253 g block of wood has the following dimensions: Length 15.24 cm Width 6.64 cm Height 3.56 cm What is the density of the wooden block?

Answers

Answer:

0.7 g/cm³

Explanation:

hey there,

< The formula for density is [tex]p = \frac{m}{v}[/tex]  where m = mass, v = volume, and p = density. An easy way to remember the formula is density equals love. I found this easy to remember because p = ♡ and when you think about it, if you split the heart in half through the middle like a fraction, it will make [tex]\frac{m}{v}[/tex] (if you don't understand what I'm saying, try writing it out and you will be able to see what I'm talking about!)

We already know that the block is 253 g so the mass is 253 g.

To find the volume, always multiply the 3 values width, length, and height whenever you are trying to find the volume of a block.

15.24 cm x 6.64 cm x 3.56 cm = 360.25 cm³

Now plug it into the formula.[tex]p = \frac{m}{v}=\frac{253}{360.25} = 0.7 g/cm[/tex]³ >

Hope this helped! Feel free to ask anything else.

Density of a substance is its mass divided by volume. Volume of the cube is calculated to 360.24 cm³ and thus the density of the cube is 0.7023 g/cm³.

What is density?

Density of a substance is the measure of its mass per volume. Thus mathematically it is the ratio of mass to the volume of th substance. Density of a substance depends on the bond type, mass, volume, temperature and pressure.

The ratio of density of a substance to the density of water is called specific gravity. If the specific gravity is greater than one the body will sink in water and if it is less than one it will float on water.

The mass of the block is given 253 g and the volume can be calculated from the product of length,breadth and height.

Volume = 15.24 cm × 6.64  cm × 3.56 cm

             = 360.24 cm³.

Density = mass/volume

             = 253 g/ 360.24 cm³

             = 0.7023 g/cm³

Hence, the density of the block is 0.7023 g/cm³.

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what is this can any body answer

Answers

Bc the light was reflecting on to the object

Which describes density? amount of volume for a given object ability of an object to take up space amount of mass in a given volume ability of an object to float in water

Answers

amount of mass in a given volume

Amount of mass in a given volume perfect describes the meaning of density. Hence option C is correct.

What is density?

Density is the term used to describe the relation between the mass of the body and their volume. Density is a property that can be used to identify substances. Each substance has a unique density.

Example: wood ball density is less as compared to metal ball because wood ball is less than metal ball.

It describes how much matter is packed into a certain volume.

D = M/V

M =Mass (gram); V = Volume (ml or cm3); D = Density (gram/cm3)

Amount of mass in a given volume perfect describes the meaning of density. Hence option C is correct.

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gottfried wilhelm von leibniz invented digital mechanical calculator called​

Answers

Answer:

It was called The Step Reconer

stepped reckoner was invented by digital mechanical calculator



Suppose now that you wanted to determine the density of a small crystal to confirm that it is phosphorus. From the literature, you know that phosphorus has a density of 1.82 . How would you prepare 20.0 mL of the liquid mixture having that density from pure samples of ( = 1.492 g/mL) and ( = 2.890 g/mL)? (Note: 1 mL = 1 .)

Answers

Answer:

Volume of [tex]CHCl_3[/tex]   = 15.31 mL

Volume of [tex]CHBr_3[/tex] = 4.69 mL

Explanation:

Given that:

the density of the mixture = 1.82 g/mL

From the density of the pure samples

The density of [tex]CHCl_3[/tex] = 1.492 g/mL

The density of [tex]CHBr_3[/tex] = 2.890 g/mL

The total volume of the liquid mixture = 20.0 mL

Suppose the volume of  [tex]CHCl_3[/tex] = P ml

and the volume of [tex]CHBr_3[/tex] = Q ml

the sum of their volumes should be equal to the total volume of the mixture

[tex]P \ ml + Q \ ml = 20 ml[/tex]  ----- (1)

However, we know that Density = mass/volume

∴ mass = density × volume

The equation can now be expressed as:

[tex]\mathtt{(Density \ of \ CHCl_3 \times Vol. \ of \ CHCl_3 ) + (Density \ of \ CHBr_3 \times \ volume \ of \ CHBr_3)} = \mathtt{ (Density \ of \ mixture \times volume \ of \ the \ mixture)}[/tex]

1.492 g/mL × P mL + 2.890 g/mL × Q mL = 1.82 g/mL × 20 mL  ---- (2)

From equation (1) ;

let Q = 20 - P

The replace the value of P into equation (2)

1.492 g/mL × P mL + 2.890g/mL × (20 - P) mL = 1.82 g/mL × 20 mL

1.492 P g + 57.8g - 2.890 P g =  36.4g

1.492 P g - 2.890 P g = 36.4g - 57.8g

-1.398 P g = -21.4g

P = -21.4g/-1.398g

P = 15.31 mL

Q = 20 - P

Q = (20 - 15.31) mL

Q = 4.69 mL

Volume of [tex]CHCl_3[/tex]   = 15.31 mL

Volume of [tex]CHBr_3[/tex] = 4.69 mL

Uun element full name

Answers

Answer: Darmstadtium

Hope that helped

Answer:

Ununnilium

Explanation:

Uun on the table of elements is Ununnilium.

Dalton’s theory states that atoms are the smallest possible parts of elements. In a chemical reaction, atoms will rearrange and form new substances with new properties. change form into completely new atoms with new properties. be destroyed and remade into new substances. be turned completely into energy.

Answers

Answer: A rearrange and form new substances with new properties.

Explanation: Got it right on Edgenuity

Answer:

a

Explanation:

got it right

what would be the best way to take water out of your coffee

Answers

drain out the water to keep the coffee grains.

HELP PLEASE ASAP I need a good explanation

Answers

Answer:

B

Explanation:

Hellium is a gas...

Solids are particles that are packed together

liquids are particles that are together but conforme to their container

gas have space between them and conform to their holder

HELP! Ethanol has a density of 0.8 g/cm3. a. What is the mass of 225 cm3 of ethanol? b. What is the volume of 75.0 g of ethanol?

Answers

Answer:

The correct answers are:

a) 180 g

b) 93.7 cm³

Explanation:

The density of a substance is the mass of the substance per unit of volume. So, it is calculated as follows:

density= mass/volume

From the data provided in the problem:

density = 0.8 g/cm³

a) Given: volume= 225 cm³

mass= density x volume = 0.8 g/cm³ x 225 cm³ = 180 g

b) Given: mass= 75.0 g

volume = mass/density = 75.0 g/(0.8 g/cm³)= 93.75 cm³≅ 93.7 cm³

Taking into account the definition of density:

the mass of 225 cm³ of ethanol is 180 g.the volume of 75.0 g of ethanol is 93.75 cm³.

Definition of density

Density is defined as the property that matter, whether solid, liquid or gas, has to compress into a given space.

In other words, density is a quantity that allows us to measure the amount of mass in a certain volume of a substance. Then, the expression for the calculation of density is the quotient between the mass of a body and the volume it occupies:

[tex]density=\frac{mass}{volume} [/tex]

From this expression it can be deduced that density is inversely proportional to volume: the smaller the volume occupied by a given mass, the higher the density.

Mass of 225 cm³ of ethanol

In this case, you know that:

Density= 0.8 [tex]\frac{g}{cm^{3} } [/tex]Volume= 225 cm³

Replacing in the definition of density:

[tex]0.8 \frac{g}{cm^{3} } =\frac{mass}{225 cm^{3} } [/tex]

Solving:

mass= 0.8 [tex]\frac{g}{cm^{3} } [/tex] ×225 cm³

mass= 180 g

In summary, the mass of 225 cm³ of ethanol is 180 g.

Volume of 75.0 g of ethanol

In this case, you know that:

Density= 0.8 [tex]\frac{g}{cm^{3} } [/tex]mass= 75 g

Replacing in the definition of density:

[tex]0.8 \frac{g}{cm^{3} } =\frac{75 g}{volume} [/tex]

Solving:

0.8 [tex]\frac{g}{cm^{3} } [/tex] ×volume= 75 g

volume= 75 g÷ 0.8 [tex]\frac{g}{cm^{3} } [/tex]

volume= 93.75 cm³

Finally, the volume of 75.0 g of ethanol is 93.75 cm³.

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How does the amount of matter change when water changes state? (2 points)
a
The amount of matter always increases as water changes state.
Ob
The amount of matter always decreases as water changes state.
Ос
The amount of matter stays the same as water changes state.
o
d
The amount of matter varies depending on how water changes state.

Answers

Answer:

C, because matter can not be created or destroyed.

Explanation:

Hey there!

I believe your answer woukd be "The amount of matter stays same as water changes state."

Hope this helps!

Have a great day!

What is the volume of the table tennis ball?
cm3
The volume of the water in the graduated cylinder rose
as some of the water was displaced by the table tennis
ball. Find the volume of the ball using the formula
Vb = Vf-Vi
where Vb is the volume of the ball, Vf is the final volume
of the water, and Vi is the initial volume of the water.
Record the volume of the ball in Table A of your Student
Guide.

Answers

The volume of the ball is the same as the volume of fluid that it displaces.

Even though the question is incomplete but i will try to help you the much i can. We have to recall that the volume occupied by the tennis ball is equal to the volume of the water displaced and this offers a convenient way of measuring the volume of solids.

The volume of the tennis ball is obtained by accurately measuring he volume of the water before putting in the tennis ball. The volume of the ball is the same as the volume of fluid that it displaces which is Vb = Vf-Vi

Learn more about displacement method: https://brainly.com/question/16610815

Answer:

40cm^3
Explanation:
I did this assignment and this was the answer so

A covalent bond is likely to be polar when ________. one of the atoms sharing electrons is more electronegative than the other atom carbon is one of the two atoms sharing electrons the two atoms sharing electrons are equally electronegative the two atoms sharing electrons are of the same elements 0

Answers

Answer:

one of the atoms sharing electrons is more electronegative than the other atom

Explanation:

A covalent bond is likely to be polar when one of the atoms sharing electrons is more electronegative than the other atom. Therefore, option (A) is correct.

What is a covalent bond?

A covalent bond can be described as a chemical link formed by the exchange of electron sets between particles. A covalent bond can be formed by equal sharing of electrons from both contributing atoms.

The pair of electrons in this type of bonding is known as shared pair or bonding pair. Covalent bonds are the sharing of bonding pairs that will ensure that the atoms gain stability in their outer shell.

Elements with very high ionization energies are incapable of transferring electrons and elements having low electron affinity cannot accept electrons. Covalent bonding takes place between two non-metallic atoms characterized by the equal sharing of electron pairs between the atoms and other covalent bonds with an electronegativity difference is more than 2.0.

Therefore, the covalent bond can be polar if one atom is more electronegative than the other atom.

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What is scientific notation

Answers

scientific notation is a mathematical way to turn large of small numbers into a simpler form.

ex. 9000000000 is  9*10^9     in scientific notation

ex. 0.000000009 is   9*10^-9 in scientific notation

the statue of liberty in new york city is approximately 305 feet tall. How many US dimes would be in a stack of the same height? Each dime us 1.35 mm thick

Answers

Answer:

It takes 62863 dimes to equal the height of the Statue of Liberty.

Explanation:

If the Statue of Liberty is 305 ft tall and a coin is 1.35mm thick, how many coins will it take to equal the height of the statue?

Convert 305 ft to mm:

1 ft = 30.48 cm

305 ft = 9296.4 cm

92 964 mm

Now, if a dime is 1.35 mm thick, how many dimes will it take to get to 92 964 mm?

1 dime = 1.35mm

X dimes = 92964 mm

X coins = 92964 / 1.35

X = 62863 dimes

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