As you have determined, the F1 is heterozygous for four loci that affect fruit segment number (A+ A 0 B+ B 0 C+ C 0 D+ D 0). This means that the F1 can produce 16 distinct gamete types, which contain different numbers of additive alleles (designated with the "+" superscript).

0 additive alleles = A0B0C0D0

1 additive allele = A+B0C0D0, A0B+C0D0, A0B0C+D0, A0B0C0D+

2 additive alleles = A+B0C0D+, A+BC+D0, A0B+C+D0, A0B+C0D+, A0B0C+D+, A+B+C0D0

3 additive alleles = A+B+C+D0, A+B+C0D+, A+B0C+D+, A0B+C+D+

4 additive alleles = A+B+C+D+

stratosphere: as the altitude increases, the air temperature increases. the stratosphere has a layer of ozone, called the ozone layer. this layer absorbs most of the ultraviolet radiation from sunlight. this results in the stratosphere being warmer.

it's not c. i took the quiz and got it wrong. so my best guess is b.

have a great day, and hope this .