For protection from the outside elements & harmful insects I would assume. Unless that's already obvious & they wanted a more in-depth answer.
The answer is 2. This is why their autosomal cells are referred to as diploid in chromosome number. The gametes have only one set of chromosomes. The homologous pair (sister chromosome) separate during meiosis I. If there was an extra chromosome in addition to this set then this would cause a condition called aneuploidy.
The kidneys.
The kidneys keep blood isotonic by removing excess salt and water through urine.
The number of protons in a neutral atom equals the number of ELECTRONS.
