How do limiting factors in an ecosystem keep the ecosystem sustainable?

1. which statement is true regarding monocytes? a. they digest pathogens. b. they produce antibodies against cancerous cells. c. they have a granular appearance under a microscope. d. they produce antibodies against microorganisms.

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

I’m doing some practice exam questions for biology, and i’m not sure how to do these 3 parts to the question.