Problem 1
A. This is a true statement because sickle cell anemia is genetic. So we can cross it off the list.
B. This is true. Those with sickle cell anemia have red blood cells that are not suitable for the parasite to grow. This applies to carriers as well to a lesser extent.
C. This is true. This is similar to choice B above.
D. This is true. Sickle cell anemia is autosomal recessive, meaning that they must inherit both sickle cell genes from each parent to have 2 in total to have the disease.
E. This is false. This contradicts what choice A is saying, which is true.
Answer: Choice E
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Problem 2
A. False. Antibiotics do not work on viruses. Viruses work differently than that of bacteria.
B. True. Antibiotics such as penicillin are very useful in killing bacteria. Though it wont get all bacteria (instead perhaps maybe something like 99.9% of all bacteria).
C. False. Antibiotics target the bacteria itself, and not the byproducts.
D. False. This is describing probiotics.
E. False. This is describing toxins.
Answer: Choice B
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Problem 3
The answer choices seem really wordy, but they all say the same basic thing except for a few key words/phrases being interchanged. Particularly, pay attention to the stuff in bold.
Those who are best adapted to the environment will likely survive and pass on their genes, so those individuals will have higher relative frequency compared to individuals not suited for the environment. Eg: desert cactus with larger needles might represent 80% of the population.
So far, we see that the answer choices are between A and D simply because of the first keyword (in bold) is "increase".
We can rule out choice D because getting a mutated gene is due to chance.
Answer: Choice A