an extracellular signaling molecule binds to cell surface receptor. this cell surface receptor changes shape and activates a trimeric g-protein. what kind of receptor is this?

Gabriel is at a stage where his body is changing physically; he is growing facial hair and building muscle. he is also just starting to make sperm. what is most likely gabriel’s age? 5 12 17 21

What causes darkening of the skin as melanin production increases

The is an estimate of the fewest number of organisms a population needs to avoid extinction. this measurement will most if the number of offspring each female in the population produces increases. if the population's this measurement will most likely increase. 1 population density, minimum viable population, carrying capacity 2 decrease, be unaffected, increase 3 death rate increase, dead rate decrease