#Question id: 11125
#Unit 7. System Physiology – Animal
In chemical synapses that involve a so-called second messenger, typically a G-protein linked to the postsynaptic receptor is activated when neurotransmitter binds to that receptor. Which of the following represents an activity performed by the activated second messenger?
#Question id: 3528
#Unit 8. Inheritance Biology
Consider the following cross:
A/a ; B/b ; C/c ; D/d ; E/e X a/a ; B/b ; c/c ; D/d ; e/e
What proportion of progeny will phenotypically resemble the first parent?
#Question id: 6974
#Unit 5. Developmental Biology
Where are the stem cells that renew the epithelium of the gut found?
#Question id: 5009
#Unit 11. Evolution and Behavior
A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped to make possible the evolution of the tetrapod limb. This type of change is illustrative of
#Question id: 4986
#Unit 11. Evolution and Behavior
A female fly, full of fertilized eggs, is swept by high winds to an island far out to sea. She is the first fly to arrive on this island, and the only fly to arrive in this way. Thousands of years later, her numerous offspring occupy the island, but none of them resembles her. There are, instead, several species each of which eats only a certain type of food. None of the species can fly, for their flight wings are absent, and their balancing organs (i.e., halteres) are now used in courtship displays. The male members of each species bear modified halteres that are unique in appearance to their species. Females bear vestigial halteres. The ranges of all of the daughter species overlap. If these fly species lost the ability to fly independently of each other as a result of separate mutation events in each lineage, then the flightless condition in these species could be an example of