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.

carbon traps heat so more of it makes it hotter causing global warming. during the ice age carbon levels in the atmosphere were low so it got very cold. so the common things between them is carbon levels in the atmosphere.