Answer:
Step-by-step explanation:
A Human cell has 46 chromosomes. (I’ll use humans to keep things simple). In sexual reproduction both humans have 23 chromosomes, in their sex cells. (Men have 23 in a sperm and women have 23 in an egg cell). These half cells merge to create 1 unique cell, that has characteristics of both male and female. The cells multiply and then a baby is born with a unique set of genes. These cause variations, and remember these variations can carry from generation to generation. As for how variations can increase a chance for survival, variations allow unique gene sets to be made, so that in case of a disease (in this case I’ll use a disease, but it could also include harsh environmental conditions), these unique gene sets may give an individual natural immunity to the disease. How can a variation decrease an organisms chance for survival? Well, s there are many ways that a unique gene set can make it difficult to survive. For example a genetic disease your family has had a history with. These diseases include, but are not limited to, cancer, diabetes, and schizophrenia.