There are cases, particularly in fruit flies, in which a normal body part grows in the wrong spot. For instance, legs on the head growing instead of antennae, or a second set of wings behind the normal pair. What can explain this?
A. These are due to misregulation of hormones from environmental contamination with pesticides.
B. These naturally occur sometimes in animals that have metamorphic development, due to different organization of homeotic gene expression in larvae versus adults.
C. These occur as a result of mutations in homeotic genes, which normally act to direct development along the anterior-posterior axis.
D. These are due to the reappearance of stem cells, which are totipotent.
Answer: C
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is associated with elevated levels of glucocorticoids. b. may lead to the excessive stimulation of neurons. c. increases blood flow to the brain, especially the hippocampus. d. results in lower levels of epinephrine and norepinephrine. e. promotes the linear growth of the skeleton
How do prokaryotic and eukaryotic chromosomes differ?
A) Eukaryotic chromosomes occur singly, and prokaryotic chromosomes occur as pairs. B) Genetic information is stored as DNA in eukaryotic cells and as proteins in prokaryotic cells. C) Prokaryotic chromosomes are not made from nucleotides. D) Prokaryotic chromosomes are not contained in a membrane-bound organelle.
What is the sex chromosome composition of a person with Klinefelter syndrome?
A. XXX B. XO C. XXY D. XYY E. YY
Half of the gametes produced by an organism with the genotype Aa will receive the A allele, while half will receive the a allele. This is a demonstration of ______.
a. independent assortment b. mutation c. random fertilization d. segregation