1. What is the most important mutation that led to human life?

The ultimate source of all genetic variation is mutation. Mutation is important as the first step of evolution because it creates a new DNA sequence for a particular gene, creating a new allele. Recombination also can create a new DNA sequence (a new allele) for a specific gene through intragenic recombination.

Explanation:

The correct answer is : Mitosis, cell growth and differentiation.

Plants increase in height due to the activity of meristem or meristematic tissue. Meristems are tissues which have capacity to divide throughout their life. Meristems are located in the apical meristems, shoot apex and root apex. Meristems divide through mitosis. The daughter cells  enlarge, stretch and differentiate into other types of cells as they mature. This causes some plants to increase in height.