Answer:
A. Pp - square pant
pp - round pant
B. 1 out of 2 or 50%
C. 1 out of 2 or 50%
Step-by-step explanation:
Assuming that square pant shape is represented by the allele P, the alternate version (round pant) will be p.
Spongebob's genotype will be Pp since he is heterozygous for his square pant shape.
SpongeSusie's genotype will be pp since she is homozygous for her round pant shape.
Pp x pp
Progeny: 2Pp, 2pp (See the attached image for the Punnet's square)
Possible genotypes and phenotypes of the children:
Pp - Square pant
pp - round pant
Chances of a child with a square shape = 1/2 or 50%
Chances of a child with a round shape = 1/2 or 50%