1. When comparing the DNA molecule to a twisted ladder, what do the rungs of the ladder represent?
3. What occurs on the sex chromosomes to determine the sex of a mammal?
4. Describe a difference between meiosis and mitosis?
5. A black guinea pig crossed with an albino guinea pig produces 12 black offspring. When the albino is crossed with a second black one, 7 blacks and 5 albinos are obtained. What is the best explanation for this genetic situation?
7. Describe one recent advance in biotechnology and its practical application.