Which cell structure is found in plant cells, but not in animal cells? (1) cell wall
(3) nucleus
(2) cell membrane
(4) cytoplasm

Average annual precipitation and are the two major features that define the biomes on earth.

Which of the following sex and generation combinations directly produces the pollen tube of angiosperms? a) male gametophyteb) female gametophytec) male sporophyted) female sporophyte

Ecologist have observed a sharp increase of sulfur dioxide in the air . what might be a possible consequence of excessive sulfur dioxide in the air ? a. acid rain b. ozone layer depletion c.ozone layer hole d.increase in sea levels