Which of the following includes a plant embryo, a food supply, and a protective covering?
a. pollen grain
b. spore
c. seed
d. gametophyte

C. seed

Explanation:

A seed is a precursor of new plant growth as it enclosed in itself the plant embryo after the process of fertilization of the male gamete pollen with the female gamete egg. The formation of seed is a characteristic feature of spermatophytes like gymnosperms and angiosperms. A seed typically composed of necessary nutrients which will sustain the young embryo and helps in the germination process. The hard protective coating prevents the loss of water from the seed so as to sustain the young embryo until it get germinated.

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.

compost can be added to topsoil as a:

pesticide