B. half of the boys are normal and half of the boys are color-blind. ( boys are most likely to get color blond than girls, the girls can also be carrier like the mother)
The question in incomplete....
A neural tube is a structure of the embryo which helps in the formation and development of the spinal cord and the brain. So when a few cells are removed from the neural tube in an experiment on frog embryos, this would cause an effect on the development of the nervous system.
The process that is illustrated is crossing over (B).
Volcanic eruption is the answer
