Cyclic gmp, or cgmp, acts as a signaling molecule whose effects include relaxation of smooth muscle cells in artery walls. in the penis, this signaling pathway and the resulting dilation of blood vessels leads to an erection. select the correct statement about the effect of viagra on this signaling pathway.

Which of the following explains why a tree is often used as a model to represent the principle of common descent

In a cladogram, what occurs at a node? a derived trait appears. evolution is stopped. an ancestor dies. the cladogram ends. aa as s as ss what are the chances that their offspring will have sickle cell anemia? 0% 25% 50% 100%

Astudent sees several ants walking up a wall following the exact same trail that an ant took earlier. she wants to apply the scientific method to determine how the ants detected the trail. which of these steps would come first in her application of the scientific method? perform an experiment by cleaning the scent away from part of the trail. draw a conclusion that the ants follow a scent trail. make a prediction about what the ants will do after she cleans away part of the trail. hypothesize that the ants are following a scent trail that the first ant left.