We wish to test if a certain vaccine developed for a
disease is effective or not. What is the best way to do
this?

A
Vaccinate 100 animals
and expose all 100 to the
disease.
B
Vaccinate 100 animals
and expose 50 of them to
the disease.

C
Vaccinate 50 animals, do
not vaccinate 50 other
animals, and expose all
100 to the disease.

D
Vaccinate 50 animals, do
not vaccinate 50 other
animals, and expose the
vaccinated animals to the
disease.

Answers

Answer 1

Answer:

The best way to test the effectiveness of a vaccine against a disease is vaccinate 50 animals, do  not vaccinate 50 other  animals, and expose all  100 to the disease (option C).

Explanation:

When testing a vaccine for effectiveness, the option is to administer the vaccine to half of the population exposed to a disease, since effectiveness should measure the performance of the vaccine within a community.

If there are 100 animals exposed to a disease, the fact that the 50 vaccinated animals do not get sick is an excellent test of how the vaccine works and what its effectiveness is.

The other 50 animals, not vaccinated, would act as a control group exposed to the same disease and sharing a certain space.

The other options are not correct because:

    A. Vaccinating the 100 exposed animals does not provide an unvaccinated control group to compare the effects of the vaccine.

    B. Vaccinating all 100 animals and exposing only 50 to the disease does not make sense, since it would not be possible to measure effectiveness in vaccinated animals that are not exposed.

    D. Vaccinating 50 animals and not vaccinating the other 50 to expose only the vaccinated animals to the disease does not make sense since the conditions of the test group and the control group should be the same.


Related Questions

What are 6 scientific facts about Cucumaria miniata?

Answers

Answer:

Cucumaria miniata is generally orange or reddish brown. They are easily identifiable by their orange coloration and branching tentacles. The body is thick and has five rows of tube feet, separated by smooth, soft skin. Pentameric radial symmetry is present in the five equally spaced rows of feet. The ossicles, which are present in all echinoderms, are small and scarcely scattered throughout the dermis.

Explanation:

hope this helps

mark me please

Which of the following forms of water pollution is most associated with mining?

Answers

Awnser: Acid Mine Drainage. Acid Rock Drainage (ARD) is a natural process whereby sulphuric acid is produced when sulphides in rocks are exposed to air and water.

Answer:

the answer is acids and heavy metals

Explanation:

2/3 of the harmful emissions are released from power plants that burn coal to generate electricity.

Which is a source of adult stem cells?
bone marrow
amniotic fluid
embryos
gametes

Answers

Bone Marrow

Bone Marrow contains skin cells in it, and it also helps fight diseases... just a bit of info about it.

Answer:

bone marrow :)

Explanation:

Name 4 greenhouse gases

Answers

Methane, overview, carbon dioxide, Fluorinated Gases

Answer:

1 Carbon dioxide.

2 Methane.

3 Nitrous Oxide.

4 Fluorocarbons.

Explanation:

Using the information recorded by seismographs, scientists learned more about the depth and density of Earth’s layers. PLEASE HURRY


True


False

Answers

Answer:

True is correct trust me

It’s true I believe

How is an ionic bond different than a covalent bond?

Answers

Answer:

Nonmetals can form different types of bonds depending on their partner atoms. Ionic bonds form when a nonmetal and a metal exchange electrons, while covalent bonds form when electrons are shared between two nonmetals.

Explanation:

What type of mutation is the mutation below:     original DNA:    3’  T A C   G C C   A G T   G G T   T C G   C A C  5’
           
mutated DNA:   3’  T A C   G C C   A C T   G G T   T C G   C A C  5’ ​

Answers

Answer:

.skugfh;'ijdOphjdkls;kjmnvjhkldf

Explanation:

Which of these igneous rocks cooled so quickly that crystals
did not form, creating a natural glassy look?

Answers

Obsidian is produced when lava cools very quickly. The lava coo ls so quickly that no crystals can form. When people make glass they melt silica rocks like sand and quartz then cool it rapidly by placing it in water. Obsidian is produced in nature in a similar way.

where is plant tissue located​

Answers

Answer:

Parenchyma – These tissues are found in the soft parts of a plant such as the roots, stems, leaves, and flowers. The cells of this tissue are loosely packed and contain large intercellular spaces between them. Each cell has a vacuole at the center.

Explanation:

What has the structure of the DNA molecule been compared to?

A straight ladder
A staircase
A twisted ladder
An escalator

Answers

It would be C. A twisted ladder

you may have read about alkaline diets that claim that you need to only eat alkaline foods in order to remain healthy according to this philosophy eating acidic Foods acidifies the blood leading to disease but our blood has several buffer systems in place explain what happens when buffers encounter additional hydrogen ions from foods will the pH of the blood decrease

Answers

Answer:

Mechanisms are activated where it is sought to lower the amount of free protons in the blood, that is, to reduce acidity, these mechanisms work between two large systems, the receptor system, the respiratory system and the renal system.

Explanation:

When a metabolic acidosis is entered, either by a food, or by a disease or even an intense physical activity, the lungs seek to generate hyperventilation, to increase the concentrations of oxygen in plasma and absolutely decrease the carbon dioxide concentration, thus not the blood becomes even more acidic.

On the other hand, the digestive system together with the sensory system, will warn this proprioception of the acidity of the plasma and will promote the dilution of these acids with a solvent, which is water, promoting the sensation of thirst.

Finally, the kidneys will seek to retain all the alkaline solutes to neutralize the physiological internal pH, and will release through the urine and the channels of acidic compounds, the products or acid metabolites to the external environment, that is, acid urine excretion.

HELP! What is the name of this organism (Picture included) Its for extra credit in my biology class

Answers

Answer: the organism is called a Tardigrade

Will give brainest!!!!
Why were some researchers known as Gestalt psychologists?
a) They only studied one part of the brain, the part where our ideas originate.
b) They studied perceptual processes by which we organize things into wholes.
c) They were taught by a German psychiatrist, Professor Wilhelm Gestalt.
d) They studied perceptual illusions and how they influenced development.

Answers

Answer:

d

Explanation:

some researchers known as Gestalt psychologists because they studied perceptual illusions and how they influenced development under the principle of Gestalt psychology. Thus option D is correct.

what is Gestalt psychology?

Gestalt psychology is a thought process which is based on human mind and behavior,  make a sense of the world around us and it suggests that we should not simply focus on every small component.

Gestalt psychology is holism, the school of psychology which has played a major role in the development of the study of human sensation and perception.

It helped to introduce the idea that human perception and  heavily influenced by our motivations and expectations. Thus option D is correct.

Learn more about Gestalt psychology, here:

https://brainly.com/question/14308306

#SPJ2

In your own words, explain how a person may taste the bitterness of PTC by using the following vocabulary words in your explanation (choose any order): trait, gene, genotype, phenotype, and alleles. Type each vocabulary word in ALL CAPS as you use it in your explanation. In this explanation, you can treat PTC taste sensitivity as a single-gene trait.

Answers

Answer:

20

Explanation:

Debate point on: girl child education is a waste​

Answers

Answer:

All you need to know is God so basically yeah this worldly education is a waste

Explanation:

The whole duty is to fear God and keep the Commandments

If you put a cell in water with a higher salt concentration then the cell has,
then water will move
1 pc
A into the cell.
B it will not move in or out of the cell.
C out of the cell.
O Dit will move in and out in equal amounts.
Which image shows a cell that has a higher concentration of salutes inside
Tin

Answers

Answer:

The answer is C

Explanation:

Water will move out of the cell through the process of osmosis.It is when water molecules moves from a dilute solution to a more concentrated solution.

I hope this helps in any way :)

3. Which ONE of the two products (outputs) of photosynthesis will the plant store in their cells for further
use?

Answers

Answer: Glucose (sugar molecules)

Explanation: Glucose is used to make more complex molecules within the plant.

Why's it good for the strangler fig to be in a relationship that's commensalism?

Answers

Because it needs water

[17 EASY POINTS 3 SCIENCE QUESTIONS ❗️❗️❗️]

How would we best define a scientific law?
A) A generalized rule to explain a body of observations.
B) An explanation of why observed events happen.
C) A mathematical formula used to explain an event.
D) A hypothesis, supported by collected data.


A ___________ describes what happens in the natural world, while a ____________ explains how things happen.
A) theory; hypothesis
B) theory; scientific law
C) scientific law; theory
D) hypothesis; scientific law



Both the Moon and the Sun influence the tides on Earth. The moon has a much greater influence though. Why is that?
A) because the Sun is much less dense
B) because the Sun is gaseous, not solid
C) because the Sun is so far away from Earth
D) because the Sun is less massive than the Moon

Answers

Answer:

B, C, B

Explanation:

Follow it in this order, Hope it helps.

Imagine that y-axis of each graph describes the rate of photosynthesis. Which of the graphs represents the
effect of light intensity on the rate of photosynthesis?
a. A
b. B
c. C
d. D

Answers

Answer:

a. A describes the effect of light intensity on photosynthesis.

Explanation:

In plants and other primary producers, photosynthesis is a biological mechanism that is vital to energy production. Energy-containing carbohydrates are derived from light, water and carbon dioxide in the form of glucose molecules.

The waste product oxygen is released as a result. Photosynthesis depends on many variables, including:

carbon dioxide concentration, ambient temperature and light intensity

It is a rate-limited reaction. Since photons or particles of light provide the energy required for the reaction, high intensities of light increase the photosynthetic rate. From the graph shown, as the intensity increases steadily, so does the rate- but at too high of an intensity, it ceases to affect the rate of photosynthesis, which becomes constant or plateaus.

Beyond this point, either the supply of carbon dioxide or the temperature limits the reaction. For instance, at high intensities tissues may even be damaged by high temperatures or heat.

Why is scientific knowledge considered durable?
A)It is open to change.
B)It is the absolute truth.
C)It outright rejects old ideas.
D)It does not accept uncertainty

Answers

The response is c hope this helps

Answer:

A)It is open to change.

Explanation:

Replacing a nitrogen base with another is an example of what type of mutation?

Answers

Answer:

The answer is c substitution

I will mark BRAINLIEST!!! Just answer this question, please!!! You will be rewarded with more than 10 points!!!

The NADH produced in glycolysis will be used in which step of cellular respiration?

1) Electron transport chain

2) Citric acid cycle

3) Krebs cycle

4) Photosynthesis

Answers

Answer:

its C

Explanation:

D
Identify structure A.
Identify structure B.
Identify structure C
С
Identify structure D.

Answers

Answer:

what structure are you trying to identify?

Explanation:

How do you think plant cells differ from animal cells? (Hint: What can plants do that animals
cannot?)
Gizmo

Answers

Plants can create their own food and energy while animals cannot.

They can take energy from the sunlight, while animals have to take energy from either other animals or plants.

Plants spread seeds by water and wind and even animal fur, but animals have to move their kin themselves.

Animals can move far and quick, while plants cannot move except growing or leaning towards a certain thing, like sunlight.

Plants cannot see, they do not have eyes. Most animals can.

Animals mostly have voices or sounds of their own. Plants do not.

Animals have an anatomy full of organs and muscles and bones. Plants don't

I hope this helps! Good luck!

Active transport moves molecules_____their concentration gradient

Answers

During active transport, molecules move from an area of low concentration to an area of high concentration. This is the opposite of diffusion, and these molecules are said to flow against their concentration gradient. Active transport is called "active" because this type of transport requires energy to move molecules.:)
Active transport moves molecules against their concentration gradient

Study the diagram about the varying pressures of Earth’s Layers.

Earth apostrophe s layers. The Crust at depth of 0 kilometers, upper mantle depth 410 kilometers, lower mantle depth 2,900 kilometers at 125 gigapascals, 2,200 degrees Celsius. Outer core depth 5,100 kilometers at 330 gigapascals, 5,000 degrees Celsius. Inner core at 364 gigapascals, 5,500 degrees Celsius.

Which is the best estimated pressure, represented in units of GPa, of the lower mantle?

Answers

Answer:

The answer is A

Explanation:

just did the time 4 learning test

the other guy was right hope this helps!

Answer: a. 110 GPa

Explanation:

DNA codes for specific proteins. Why are proteins so vital to the human body? Provide a couple of examples.

Answers

Answer:

-They do most of the work in cells

-They are required for the structure, function, and regulation of the body's tissues + organs

Answer:

they help us to grow

Explanation:

protein is a body building food

Most earthquakes occur in the center of continental plates. True False​

Answers

Answer:

Explanation:

False and plzz give me brainliest

Answer:

false, they are usually where the plate boundary is

Pls someone help before this is due

Answers

The answer is D, 0.3km/min
The slope of the line is 3km/10min
3/10 = 0.3, 10/10 = 1 so 0.3km/1min
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