Image At which point is cool air circulating beneath warm air?
Warm and cold air fronts with points labeled 1 through
- 1: cold air entering from the left and moving down. 2:
Hlouds with rain. 3: warm air entering from the right and
moving up. 4: warm air entering from the top left and
moving down toward the clouds.

During endocytosis, cells expel what they don't need take in what they need shrink due to loss of water

Which of the following statements is true about the relationship between genetic variation and natural selection? a. genetic variation must be present in a population before natural selection can act on it. b. genetic variation arises in a population as a result of natural selection. c. natural selection can act on a population whether there is genetic variation within the population or not. d. after natural selection acts on a population, the amount of genetic variation in the population always increases.

Por qué crees que los huevos con cáscara se llaman amnióticos?