Question 2
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2. It can be inferred from the passage that the morphogenetic determinants present in the early embryo are
Let's start by considering some key points from the third paragraph:
- Morphogenetic determinants are found in the cytoplasm of the unfertilized egg cell (outside the nucleus).
- The morphogenetic determinants are inactive, but become active when the egg is fertilized
- The morphogenetic determinants are not distributed homogeneously (not distributed evenly).
Let's now consider the answer choices:
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(A) located in the nucleus of the embryo cells
Since the morphogenetic determinants are located
outside the nucleus, (A) is out.
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(B) evenly distributed unless the embryo is not developing normally
Since the morphogenetic determinants are NOT
distributed homogeneously (i.e. NOT distributed evenly), we can eliminate (B).
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(C) inactive until the embryo cells become irreversibly committed to their final function
According to paragraph 3, the morphogenetic determinants become
active when the egg is fertilized. Since the embryo develops AFTER the egg is fertilized, the morphogenetic determinants in the early embryo must already be
active. Because (C) claims that the morphogenetic determinants in the early embryo are
inactive, it's wrong. Eliminate (C).
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(D) identical to those that were already present in the unfertilized egg
The morphogenetic determinants in the unfertilized egg are
inactive, while the morphogenetic determinants in the early embryo are
active. So the morphogenetic determinants in the unfertilized egg can't be identical to those in the early embryo, and (D) is out.
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(E) present in larger quantities than is necessary for the development of a single individual
In the first paragraph, we learn that if an embryo is separated into two parts "at an early stage of its life," it develops into
two normal embryos. Since one early embryo can develop into two embryos when cut in half, there must have been enough morphogenetic determinants in the early embryo for both of them (i.e. more than was needed for a
single individual). So (E) is correct.