Dolphins have the same arm structure as wolves. What type of evidence for evolution does this represent?


A. DNA

B. vestigial structures

C.homologous structures

D. embryology

Answers

Answer 1
The answer is C, homologous structures

Related Questions

Suppose a chemical engineer studying a new catalyst for the Haber reaction finds that liters per second of dinitrogen are consumed when the reaction is run at and the dinitrogen is supplied at . Calculate the rate at which ammonia is being produced. Give your answer in kilograms per second. Be sure your answer has the correct number of significant digits.

Answers

The question is incomplete. Here is the complete question.

In the Haber reaction, patented by German chemist Fritz Haber in 1908, dinitrogen gas combines with dihydrogen gas to produce gaseous ammonia. This reaction is now the first step taken to make most of the world's fertilizer. Suppose a chemical engineer studying a new catalyst for the Haber reaction finds that 505. liters per second of dinitrogen are consumed when the reaction is run at 172.°C and 0.88 atm. Calculate the rate at which ammonia is being produced. Give your answer in kilogram per second. Be sure your answer has the correct number of significant digits.

Answer: Rate = 0.41 kg/s

Explanation: The balanced Haber reaction is

[tex]N_{2}+3H_{2}\rightarrow2NH_{3}[/tex]

As all the components are gases, we can use Ideal Gas Law, which relates Pressure (P), Volume (V), Temperature (T) and Moles (n) in the following formula:

PV = nRT

where

R is gas constant and, in this case, is R = 0.082 L.atm.K⁻¹mol⁻¹

T is in Kelvin

Converting Celsius in Kelvin:

T = 273 + 172

T = 445 K

Calculating moles

[tex]n=\frac{PV}{RT}[/tex]

[tex]n=\frac{0.88(505)}{0.082(445)}[/tex]

n = 12.18 moles

According to the balanced equation, for 1 mol of dinitrogen gas consumed, 2 moles of ammonia is produced.

With 12.18 moles of dinitrogen, the reaction will result in

2(12.18) = 24.36 moles of ammonia

Molar mass of ammonia is M = 17.031 g/mol.

In 24.36 moles, there are

[tex]m=n.M[/tex]

m = 24.36.17.031

m = 414.87 grams

Since it's asking in kilograms: m = 0.41 kg.

In the beginning, it is said that dinitrogen gas is consumed at a rate of liters per second. So, the production rate of ammonia will be 0.41 kg/s.

Showing little or no charge is called​

Answers

an atom. An atom has no charge. The number (and charge) of protons in atom's nucleus is balanced by the electrons orbiting the nucleus. If it had charge it would be called an ion.
An atom? The first guy sounds smart.

Which nitrogen bases always pairs with thymine?​

Answers

Answer:

The four different bases pair together in a way known as complementary pairing. Adenine always pairs with thymine, and cytosine always pairs with guanine.

Explanation:

Cameron connects a battery, a lightbulb, and electrical wires to make a simple circuit. Which choice correctly lists the forms of energy found in the circuit?
chemical only
chemical and electrical
chemical, electrical, light
chemical electrical, light, heat

Answers

Answer:

Chemical,electrical,light,heat

Answer:

chemical electrical, light, heatExplanation:

Which element is oxidized in the following reaction Mn²⁺ + 2 K → Mn(s) + 2 K⁺ ?

Answers

Potassium is oxidized (k)
Leo ger is the nuemonic
- loss electrons = oxidized
- gain electrons = reduced

You can see K gains a positive charge so it is safe to assume it lost some (negatively charged) electrons

You want to clean a 500-ml flask that has been used to store a 0.9M solution. Each time the flask is emptied, 1.00 ml of solution adheres to the walls, and thus remains in the flask. For each rinse cycle, you pour 9.00 ml of solvent into the flask (to make 10.00 ml total), swirl to mix uniformly, and then empty it. What is the minimum number of such rinses necessary to reduce the residual concentration of 0.00001 M or below

Answers

Answer:

In the 5th cycle rinse, the residual concentration of the solution is < 0.00001M

Explanation:

In each rinse cycle, the dilution that you are doing of the solution is from 1.00mL to 10.00mL, that is a dilution of 10

In the first rinse the concentration must be of 0.9M  10 = 0.09M

2nd = 0.009M

3rd = 0.0009M

4th = 0.00009M

5th = 0.000009M →

In the 5th cycle rinse, the residual concentration of the solution is < 0.00001M

P4+O2=P2O3
What’s the balance of this equation?

Answers

Explanation:

P₄+O₂=P₂O₃; non-balanced

P₄+O₂=2P₂O₃; to add '2' on the right side; non-balanced

P₄+3O₂=2P₂O₃. to add '3' before O₂ in the left side; balanced

Benzophenone has a normal freezing point of +48.1 oC, with freezing point depression constant Kfpt = − 9.78 oC/m. A 0.1500 molal solution of ionizing salt had a freezing point of +44.0 oC. What is the van't Hoff (ion dissociation) constant i for this salt? (i.e., the average number of ions produced in the solution.) Report 3 significant digits.

Answers

Answer:

i = 2.79

Explanation:

The excersise talks about the colligative property, freezing point depression.

Formula to calculate the freezing point of a solution is:

Freezing point of pure solvent - Freezing point of solution = m . Kf . i

Let's replace data given. (i = Van't Hoff factor, numbers of ions dissolved in solution)

48.1°C - 44°C = 0.15 m . 9.78°C/m . i

4.1°C / (0.15 m . 9.78°C/m) = i

i = 2.79

In this case, numbers of ions dissolved can decrease the freezing point of a solution, which is always lower than pure solvent.

which two substances are among the four major types of organic compounds made by living things
A.lipids
B.water
C.carbon dioxide
D.Nucleic acids


will give brainliest

Answers

Which two substances are among the four major types or organic compounds made by living things, The answer C,
would be carbon dioxide

Classify each as acidic or basic - pH 9 - pH 2.3 - pH 11 - pH 5 - solution where the concentration of hydronium ions [H ] is 0.0056 M - solution where the concentration of hydronium ions [H ] is 3.45 E-9 M.

Answers

Answer:

pH = 9: Basic; pH = 2.3: acidic; pH = 11: basic; pH = 5: Acidic; [H⁺] = 0.0056M: Acidic; [H⁺] = 3.45E-9M: Basic

Explanation:

A solution is defined as acidic when pH < 7 and as basic when pH > 7.

Also, pH = -log[H⁺].

Thus:

pH = 9: >7 → Basic

pH = 2.3: <7 → Acidic

pH = 11: >7 → Basic

pH = 5: <7 → Acidic

[H⁺] = 0.0056M, pH = -log0.0056M = 2.25: <7: Acidic

[H⁺] = 3.45E-9M, pH = 8.46: > 7: Basic

Which is a gas at room temperature A.aluminum B.nitrogen C.potassium D.sodium

Answers

Answer:

B.nitrogen

Explanation:

Nitrogen is a gas at room temperature.

How many moles of hydrogen gas are present in 65.0 liters at STP?
1456 moles
1.45 moles
3.00 moles
2.90 moles

Answers

Answer:

2.9moles of hydrogen gas

Explanation:

convert liters to dm³

since 1liter= 1dm³

thus, 65.0liters = 65.0dm³

number of moles = volume given/22.4dm³

= 65.0/22.4

=2.9moles

A compound with molecular formula C5H10Br2 displays the following 13C NMR along with the DEPT-90 and DEPT-135 13CNMR spectra. What is the structure for this compound?

Answers

Answer:

Explanation:

The correct structure for the compound C5H10Br2 is:

Br -- CH₂ -- CH₂ -- CH₂ -- CH₂ -- CH₂ -- Br

         1          2         3         4         5

The name of the required compound is 1,5-dibromopentane.

The DEPT spectroscopy is applied to differentiate between CH₃, CH₂, and CH groups.

Assuming the DEPT is up, this shows a positive peak which illustrates CH₃ group

Assuming the DEPT is down, this shows a negative peak which illustrates CH₂ or CH group

C-13 NMR with DEPT-135

The negative peak in DEPT at 26.77 ppm illustrates CH₂ or CHThe negative peak at 31.85 ppm illustrate CH₂ or CHThe negative peak at  33.24 ppm illustrate CH₂ or CH

The carbon analysis is:

Assign            ppm

1                     33.24

2                     31.85

3                     26.77

4                     31.85

5                    33.24

Do you think crystals formed in conditions that were stable or did they change often?

Answers

Answer:

They were made in unstable conditions

Explanation: Im smarty pants

The total thermal energy of a system depends jointly on the temperature, total number of in the system _______________, and the _______________of the material. *


1. Molecules/State

2. Molecules/Heat

3. Matter/Heat

4. Atoms/State

Answers

Answer:

Molecules/State

Explanation:

We know from the kinetic molecular theory that matter is made up of molecules. These molecules are in constant motion at various velocities and energies.

The total thermal energy refers to the total kinetic energies of these particles. It depends on the temperature of the system, the energies of the molecules present in the material and the arrangement of the object's molecules (states of matter).

URGENT!!! Compare the relative strength of the two forces A and B. Explain how you determined this comparison by identifying the forces

Answers

Answer:

A= Covalent bonding.

B = Dispersion forces.

Explanation:

This particular question wants to test our knowledge on chemical attractions in molecules. Kindly check the picture attached to get a glimpse of the two forces being compared here.

The force of attraction in B is known as the Dispersion forces. It is the kind of forces of attraction that happens when hydrogen bonds do not happen. Literarily, when Hydrogen  atoms reacts with more electronegative atoms such as oxygen, Fluorine and Nitrogen, the kind of bond that will be formed will be an hydrogen bond. So, if hydrogen bond is not formed, then a weaker bond will be formed which is the Dispersion forces of attraction. Hence, B is the Dispersion forces.

Covalent bonds are the kind of bonds that involves that atoms shares electrons in order for chemical bonding to occur. Although, there is H2O which is a polar covalent bond. There are other compounds that are not polar such as CS2 and CH4. Therefore, the kind of attraction in A is covalent bonding.

Identify three farming practices that contribute to desertification. Discuss how each practice can be avoided and how changing the practice will affect the soil.

Answers

Answer:

See explanation

Explanation:

Poor irrigation: When too much water is used during irrigation or water is inefficiently used for irrigation purposes, there could be an overall decrease in the availability of water resources leading to vegetation loss and desertification. Therefore, water resources should be properly managed to avoid desertification.

Overgrazing: Overgrazing refers to excessive grazing of a grassland. When livestock are allowed to overgraze on a particular area, there is vegetation loss and consequent desertification. Grazing practices should be organized in such a way that grasslands are not subjected to overgrazing.

Poor tillage practices: Poor tillage practices such as continuous cropping makes the soil more porous and exposes the soil to erosion. There may be vegetation loss and finally desertification. Sustainable tillage practices such as shifting cultivation and bush fallowing should be adopted.

if LiCl and MgBr2 were to enter into a chemical reaction which member of MgBr2 will chlorine replace?

Answers

Answer:

It replaces Br in MgBr2.

Explanation:

Hello!

In this case, when carrying out double displacement reactions, we need to take into account that cations and anions are switched; thus, when LiCl and MgBr2 react, since Li and Mg are the cations, Br and Cl switch as shown below:

[tex]2LiCl+MgBr_2\rightarrow 2LiBr+MgCl_2[/tex]

Thus, chlorine replace Br in MgBr2 to form MgCl2.

Best regards!

WHY IS IT IMPORTANT FOR A POPULATION TO NOT ALL BE IDENTICAL?

Answers

Answer:

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c/dlvpkvecfevmsovs

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vmfbmefbbbeblpbjr90rq

Explanation:


What is the structure formula of c10h18

Answers

Answer: I'm not 100% sure this is the formula but I hope it still helps! :)

Explanation:

Bornane; Cyclodecene; Decalin; Decynes. 1-Decyne; 2-Decyne; 3-Decyne; 4-Decyne; 5-Decyne, also known as dibutylethyne; Spirodecane

How many orbitals in an atom can have each of the following designations:
(a) 1s;
(b) 4d;
(c) 3p;
(d) n=3?

Answers

Answer:

(a) 1s; has one orbital

(b) 4d; has five orbitals

(c) 3p; has three orbitals

(d) n=3 has nine orbitals

Explanation:

Electrons in an atom are always in constant motion, making it hard to predict there exact position. However, the most probable locations electrons can be be found are described with the terms shells, subshells and orbitals. A shell contains subshells and orbitals are found within subshells. The shells are given names such as K, L, M, N, which correspond to the principal quantum numbers, n = 1, 2, 3, and 4 respectively. There are 4 major types of subshells that can be found in a shell. They are named as s, p, d, f. Each subshell is composed of several orbitals.

a. 1s; the s subshell has only one orbital. Therefore, the 1s subshell has one orbital

b. 4d; the d subshell has five orbitals. Therefore, the 4d subshell has five orbitals

c. 3p; the p subshell has three orbitals. Therefore, the 3d subshell has  three orbitals

d. n = 3; the shell with n = 3 has the following subshells, 3s, 3p, 3d.the number of orbitals will be 1 + 3 + 5 = 9 orbitals. Therefore, the number of orbitals in n = 3 is nine orbitals

1. Radiation with a frequency of 1.85 MHz, falls in the radio wave region. What is the wavelength (in nm) of this electromagnetic radiation?




(HINT: Hz is "cycles per second" and should be replaced by 1/s as a unit in the calculation. First convert MHz to Hz (106) also the final answer convert to nm. (10-9)




2. What is the frequency of visible light, which has a wavelength of 625 nm? What color is the wave?





(HINT: Notice for final answer that nm must be converted to m in order for the units to cancel properly)

Answers

Answer:

1. 1.62×10¹¹ nm

2. 4.8×10¹⁴ Hz

Explanation:

1. Determination of the wavelength.

We'll begin by converting 1.85 MHz to Hz. This can be obtained as follow:

1 MHz = 10⁶ Hz

Therefore,

1.85 MHz = 1.85 MHz × 10⁶ Hz / 1 MHz

1.85 MHz = 1.85×10⁶ Hz

Next, we shall determine the wavelength of the electromagnetic radiation. This can be obtained as follow:

Frequency (f) = 1.85×10⁶ Hz

Velocity of electromagnetic radiation (v) = 3×10⁸ m/s

Wavelength (λ) =?

v = λf

3×10⁸ = λ × 1.85×10⁶

Divide both side by 1.85×10⁶

λ = 3×10⁸ / 1.85×10⁶

λ = 162.16 m

Finally, we shall convert 162.16 m to nm. This can be obtained as follow:

1 m = 10⁹ nm

Therefore,

162.16 m = 162.16 m × 10⁹ nm / 1 m

162.16 m = 1.62×10¹¹ nm

Thus, the wavelength of the electromagnetic radiation is 1.62×10¹¹ nm

2. Determination of the frequency.

We'll begin by converting 625 nm to m. This can be obtained as follow:

1 nm = 10¯⁹ m

Therefore,

625 nm = 625 nm × 10¯⁹ m / 1 nm

625 nm = 6.25×10¯⁷ m

Finally, we shall determine the frequency the visible light as follow:

Wavelength (λ) = 6.25×10¯⁷ m

Velocity of light (v) = 3×10⁸ m/s

Frequency (f) =?

v = λf

3×10⁸ = 6.25×10¯⁷ × f

Divide both side by 6.25×10¯⁷

f = 3×10⁸ / 6.25× 10¯⁷

f = 4.8×10¹⁴ Hz

Therefore, the frequency of the visible light is 4.8×10¹⁴ Hz

Draw the kinetic and thermodynamic addition products formed when one equivalent of HBr reacts with the diene .

Answers

Answer:

See explanation and images attached

Explanation:

The addition of HBr to the diene could yield either a kinetic or thermodynamic product. The kinetic product is formed faster while the thermodynamic product is more stable and formed at equilibrium.

Recall that the alkene that is surrounded by more alkyl groups is more stable. Also, the carbocation undergoes rearrangement to form a more stable carbocation intermediate that ultimately leads to the formation of the thermodynamic (1,4) product which predominates.

The structures of the two products are shown in the image attached to this answer.

How much heat must be used to raise the
temperature of 180. g water from 19° C to 96°C?
The specific heat of water is 4.18 J/gºC.

Answers

Answer:

Q =  57934.8 J

Explanation:

Given data:

Mass of water = 180.0 g

Initial temperature = 19°C

Fina temperature = 96°C

Specific heat capacity of water = 4.18 J/g.°C

Heat absorbed = ?

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT = 96°C - 19°C

ΔT = 77°C

Q = 180.0 g×4.18 J/g.°C×77°C

Q =  57934.8 J

Name the energy store that two electrical
charges have when they attract or repel each
other.​

Answers

Answer:

In contrast to the attractive force between two objects with opposite charges, two objects that are of like charge will repel each other. That is, a positively charged object will exert a repulsive force upon a second positively charged object.

Explanation:

Hope it has answered your question

What is the atomic number?
pls help.

Answers

Answer:

8

Explanation:

what state of matter travels in straight lines

Answers

Answer:

light

Explanation:

light is plasma, which is a state of matter

After running, Ollie’s blood pressure was high. His nervous system sensed this and sent a message to decrease heart rate and blood flow.

Answers

Answer:

Circulatory

Explanation:

Ammonium phosphate is an important ingredient in many solid fertilizers. it can be made by reacting aqueous phosphoric acid with liquid ammonia. calculate the moles of ammonium phosphate produced by the reaction of 0.085 mol of ammonia. be sure your answer has a unit symbol, if necessary, and round it to the correct number of significant digits.

Answers

Answer:

0.028 mole of ammonium phosphate, (NH₄)₃PO₄.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

H₃PO₄ + 3NH₃ —> (NH₄)₃PO₄

From the balanced equation above,

3 moles of NH₃ reacted to produce 1 mole of (NH₄)₃PO₄.

Finally, we shall determine the number of mole of (NH₄)₃PO₄ produced by the reaction of 0.085 mole of ammonia, NH₃. This can be obtained as follow:

From the balanced equation above,

3 moles of NH₃ reacted to produce 1 mole of (NH₄)₃PO₄.

Therefore, 0.085 mole of NH₃ will react to produce = (0.085 × 1)/3 = 0.028 mole of (NH₄)₃PO₄.

Thus, 0.028 mole of ammonium phosphate, (NH₄)₃PO₄ were obtained from the reaction.

When a substance undergoes a chemical change, its identity does not change.
O True

O False

Answers

Answer:

False

Explanation:

Chemists make a distinction between two different types of changes that they study—physical changes and chemical changes. Physical changes are changes that do not alter the identity of a substance. Chemical changes are frequently harder to reverse than physical changes.

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