I would say DNA needs to be in a double helix so it can be unraveled and duplicated during cell mitosis
Answer:People look at the fossil record and think the early history of many animals is filled with giants, but not for whales. It's only in recent geological times that whales have achieved really large sizes
The correct answer is emphysema.
This respiratory disease occurs when alveoli get enlarged, and thus cause chronic lung inflammation and later on lung fibrosis as well. This person then finds it extremely hard to breathe properly, as airways tend to collapse during expiration.