Question

If 2 parents-both heterozygous for particular traits in a dihybrid cross are mated, how many different phenotypes will result in the f2 generation ?

Answer 1

If the parents are both heterozygous for particular traits their genotype would be: AaBb x AaBb ( this cross would be the F1 generation while the P generation is the one that originated the parents).
This cross would result in the folowing genotypes:
AABB
AaBB
Aabb
aaBB
aaBb
aabb
Dominant for A and B: 9/16
Dominant for A but recessive for B: 3/16
Recessive for A but dominant for B: 3/16
Recessive for A and B: 1/16
 ratio: 9:3:3:1
To answer you the possible phenotypes is difficult because your question is missing information about what each gene does, but I know it would be 4 different phenotypes.