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daser333 [38]
2 years ago
5

When Jenner developed the first vaccine he was using the observation of milk maids who

Biology
2 answers:
vova2212 [387]2 years ago
8 0
A. after having cowpox they where immune to smallpox HOPE THIS HELPS
Scrat [10]2 years ago
8 0

Ans. Option (a).

Edward Jenner first developed a successful vaccine for smallpox in 1796. He used the observation of milk maids who were become immune to smallpox after being infected by cowpox as they were became immunized to smallpox.

It is because the virus that causes cowpox is similar to smallpox virus. When those milkmaids got infected with cowpox, their immune system made antibodies that can also kill virus for smallpox and thus, they did not get infected by smallpox.

Thus, the correct answer is option (a).

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List three facts about the specific body system for endocrine system
Scrat [10]

Answer:

The endocrine system is a chemical messaging network. Endocrine glands secrete hormones, which are carried by the circulatory system throughout the body. The primary endocrine glands are the pituitary, hypothalamus, pineal gland, thyroid, parathyroid, adrenal, pancreas, ovary, and testis. Hormones maintain homeostasis in the body.

Explanation:

Hope this helps!

7 0
3 years ago
____, which can be natural or artificial, are chemical substances added to food to slow the growth of the microorganisms that ca
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Preservatives

Explanation:

8 0
3 years ago
Which best describes the reliability of the information?
KatRina [158]

Answer:

no

Explanation:

no

6 0
3 years ago
Human health is unaffacted by enviromental limiting factors
SOVA2 [1]

Answer:

The given statement is False.

Human health is affected by the environment limiting factors. The limiting factors like food, water and some other resources are responsible for the human health and hygiene. The both the biotic and abiotic factors are responsible for the human health.

6 0
3 years ago
Animals with a three-chambered heart would include:_______
Setler79 [48]

Animals with a three-chambered heart would include Amphibians.

  • Amphibians have three-chambered which comprises of two Atria and one ventricle. Examples of Amphibians include Frog, Toads, Salamanders.
  • In Amphibians heart blood from the single ventricle travels to the lungs, skin, and body, where it is oxygenated. Before being pumped out of the heart, deoxygenated and oxygenated blood are mixed in the ventricle.
  • This is because the Amphibians have low rate of metabolism and thus requires less oxygen for their metabolism.
  • As a result heart's load to deliver oxygenated blood to body is lowered.

Thus, from the above pointers we can conclude that only Amphibians from the option have three-chambered heart.

Learn more about Amphibians:

brainly.com/question/27961653

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4 0
1 year ago
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