A.Energy,Water,Sunshine, Protection
But an egg or sperm only has one. That one is chosen at random, through a process called meiosis. When meiosis messes up, you can end up with to many or too few chromosomes. One extra chromosome in a egg or sperm means three in the fertilized egg and so trisomy.
Answer:
the inner most layer of the earth is known as the core it is divided into inner core and outer core . it comprises of a high concentration of nickel and iron. here is your answer thanku
