A zygote is a fertilized egg formed by an egg and a sperm. The zygote undergoes many mitotic events as it develops into a solid ball of cells (ie, blastomeres) called a blastula. What changes occur in this early cleavage?
A. During the initial stages of cleavage, there is a tremendous increase in the number and size of blastomeres.
B. During the initial stages of cleavage, there is no increase in the number of cells of the developing organism, but the size of the cells increases.
C. During the initial stages of cleavage, there is a tremendous decrease in the number and size of blastomeres.
D. During the initial stages of cleavage, there is a tremendous increase in the number of cells coupled with a decrease in the size of the cells composing the developing organism.
Answer: D
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A) artificial selection B) directional selection C) stabilizing selection D) disruptive selection E) sexual selection
What are the two main steps that must happen to a protein in order for it to be catabolized and broken
down by the citric acid cycle?
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A CD4+ T cell binds to an antigen only if this antigen
a. is in a complex with a class I MHC protein. b. is in a complex with a class II MHC protein. c. is in a complex with a class III MHC protein. d. is NOT in a complex with MHC proteins. e. is presented on the surface of a B cell.
The processes of photosynthesis and cellular respiration are complementary. During these energy conversions, some energy is
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