Question

like many of the traits you learned about in the last lesson, sickle cell anemia is genetic, meaning it is passed down from parents to their offspring. by the end of this lesson you will have learned its unique pattern of inheritance and used it to predict its occurence in children.

people with the condition have abnormally shaped red blood cells that die sooner. over time this leads to dangerously low levels of red blood cells and can be fatal if left untreated. sickle cell disease affects individuals around the world, including 100,000 americans.

which of the following describes sickle cell anemia:
it only occurs in african americans.
it is incredibly rare. (less than 10,000 have it in the us)
it is contagious.
if one of your parents has it, then you will

Explanation:

1. Analyze the first option: The text says sickle cell disease affects individuals around the world, including 100,000 Americans, so it's not only in African Americans. Eliminate this.
2. Analyze the second option: The text states it affects 100,000 Americans, so it's not less than 10,000. Eliminate this.
3. Analyze the third option: Sickle cell anemia is genetic (passed from parents to offspring), not contagious (which would be spread by contact). Eliminate this.
4. Analyze the fourth option (assuming the full option is about inheritance, like if one parent has it, there's a chance to inherit): Since it's genetic, inheritance patterns apply. So this option (if it's about inheritance likelihood) would be correct. But since the options are cut off, but from the first part, the correct reasoning is that the other options are wrong. Wait, maybe the fourth option is something like "It is a genetic disorder passed from parents" (but the user's options are cut, but from the given, the first three are wrong. Wait, maybe the original question has a fourth option that's correct. But based on the text: sickle cell is genetic, so if the fourth option is about inheritance (like if one parent has it, you can inherit), that's correct. But since the options are partially shown, but from the given three wrong ones, the correct one (even if cut) would be the one related to genetic inheritance. But maybe the user's options were mistyped. However, based on the given options:

Wait, the user's options:

• It only occurs in African Americans. (Wrong, as affects people worldwide)
• It is incredibly rare. (Less than 10,000 have it in the US) (Wrong, text says 100,000 Americans)
• It is contagious. (Wrong, it's genetic, not contagious)
• If one of your parents has it, then you will... (Assuming the rest is about inheritance, which is correct as it's genetic. So this option, even if cut, is the correct one. But since the options are not fully shown, but from elimination, the correct answer would be the fourth option (the one about parent inheritance), but since the user's options are partially visible, but based on the text, the correct description is related to its genetic inheritance. But maybe the original question's fourth option is correct. So the answer is the fourth option (even if cut), but since the user's options are as given, we have to assume. Wait, maybe the user made a typo, but based on the text, the correct answer is the one related to genetic inheritance, so the fourth option (the one starting with "If one of your parents has it, then you will...") is correct.

Answer:

The correct option (assuming the fourth option is about genetic inheritance, e.g., "If one of your parents has it, then you will have a chance to inherit it" or similar) is the fourth option (the one with the parent - related statement). But based on the elimination of the first three:

1. It only occurs in African Americans. - Wrong (affects people worldwide).
2. It is incredibly rare. (Less than 10,000 have it in the US) - Wrong (100,000 Americans have it).
3. It is contagious. - Wrong (genetic, not contagious).

So the correct answer is the fourth option (the one starting with "If one of your parents has it, then you will...").