What does photosynthesis create that humans need?

How does an angiosperm prevent self pollination

How does a gymnosperm prevent itself from pollinating the same tree

Guinea pig coat color is determined by a single gene. the allele for black coat color is dominant to brown. in a cross between twoblack-haired guinea pigs, 20 offspring are born. if both parents were heterozygous, probability would predict that approximately howmany of the 20 offspring would have brown hair?