Explain why two parents with hartnups disease will not have any normal children, but two parents without hartnups disease could have a child with disease?

Two parents without Hartups disease could have a child with the disease because the parents could be carriers of the disease. If they are carriers of the disease, their offspring has a 50% of acquiring the disease.

the answer to your question is tooth decay.

1. b.

2. d.

3. a.

5. d.

6. c.

these are the only ones that i know, i hope this , and good luck.