Without genetic variation, some of the basic mechanisms of evolutionary change cannot operate. Consider the three primary sources of genetic variation. 1. mutations
2. gene flow
3. sexual reproduction

Review the diagram involving meiosis and fertilization. In all three scenarios, other than the principles governing meiosis, what is the source of genetic variation?
A)mutation
B) gene flow
C) nondisjunction
D) random assortment

Been sitting here trying to take this test and don't know this answer! place the events of a feedback mechanism associated with body temperature in the correct order. ·nerve cells send message from skin to the brain ·body returned to normal temperature around 98.6 degrees f ·temperatures regulation center in the brain sends out signals ·body temperature exceeds 98.6 degrees f ·sweat glands throughout the body activate to cool off skin surface it is a 1 through 5 question in biology!