Question

Please describe the relationship between I 1 and III 1 shown in the pedigree show. (written I 1 / III 1)

A Father/son
B grandfather/daughter
C mother/son
D grandmother/grandson

I think it's D?

Answer 1

A circle represents female while a square, a male.
The I generation produces 3 off springs with one male mating with a female to produce a male offs spring.
Therefore, I 1 and III 1 are grandmother and grandson.
The answer is D.