Male mallards have had emerald green head feathers
and wings with metallic blue patches for hundreds of
years, whereas female mallards have been drab,
brown-feathered ducks. This phenotypic situation
suggests that mallards may be an example of
a. directional selection.
b. polyploidy.
c. allopatric speciation.
d. disruptive selection.
e. sexual selection
Answer: e
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After removing some freshly baked cookies from the oven, you accidentally brush the side of the pan with your bare hand. Your reflexes kick in and you immediately draw your hand away. What is the proximate cause of this behavior?
A. For millions of years, your ancestors survived in part because they avoided damaging heat, and thus were able to pass on heat-avoiding genes to you. B. Drawing your hand away quickly when it encounters high heat prevents injury, thereby increasing your chances to survive and reproduce. C. Sensory receptors in the skin of your hand sent a signal to interneurons in your spinal cord, which subsequently signaled the motor neurons in your arm and hand to contract, drawing your hand away. D. You perceived the heat, judged that it would cause a burn if you left your hand in place too long, and made a conscious decision to pull your hand away.
Insertion or deletion of a nucleotide in a gene causes a type of mutation called a(n) ____________________ mutation. Fill in the blank(s) with the appropriate word(s)
When ____ comes in contact with acidic gastric juices, it is converted to ____, the main digestive enzyme of the
stomach. a. carboxyamylase; amylase b. amylase; carboxyamylase c. pepsin; pepsinogen d. pepsinogen; pepsin e. bolus; chyme
What is the name of the protein that appears to regulate the entry of cells into an S phase? This protein is also known as the "guardian of the genome."
A) cyclin B) p53 C) phosphokinase D) p34 E) p102