One snail variety has an inherited condition that changes the shell thickness. $S^t S^t$ have thick shells. $S^t S^n$ have thin shells. $S^n S^n$ do not survive. Two heterozygous snails are crossed. What is the probability that a surviving snail in the next generation is a heterozygote?
- A0.00
- B0.25
- C0.50
- D0.67