During the process of fertilization, which step happens first? a. the sperm's nucleus enters the egg cell. b. enzymes break down the protective layer of the egg cell membrane. c. a sperm attaches to a binding site on the egg cell membrane. d. the cell membrane of the egg cell changes. e. the sperm looses its tail.

Asquirrel population lives in an area. over many years, a river in that area grows wider and stronger, eventually forming a canyon. the squirrel populations on the two sides of the canyon can no longer mate with each other and ultimately form distinct species. this is an example of

You want to cultivate some exotic plants at your farm. however, the climate is chillier than the temperature range favorable to the crop. which is the best method to use for the cultivation of this exotic crop? a. use a crop rotation method b. use a lot of fertilizer c. prepare the seed bed properly d. use a greenhouse e. use irrigation

Where is the nictitating membrane found? a. between the eyelid and the eyeball b. between the retina and the optic nerve c. between the outer and middle ear d. in the organ of corti in the middle ear