What is a condition in which a cell has only one copy of one of its chromosomes called?

If a set of instructions that determines all of the charactersitics of an organism is comparedto a book,and a chromosme is compared to chaper in the book,then what might be compared to a paragraph in the book?

Which of the following is a possible reason for sleep? a) growth b)digestive c)speed d)intelligence

What environmental cues and landmarks do the geese use to determine the timing and direction of their migration over the mountains? how do they find their way?