Biology Questions

Genetic drift or allelic drift is the change in the relative frequency in which a gene variant (allele) occurs in a population due to random sampling and chance.

When is genetic drift a major factor in evolution is

* When there is low gene flow.

* When there is no selective pressure.

* When there is a bottleneck.

The process by which bacteria convert nitrogen gas (N2) into ammonia (NH3) is called Nitrogen Fixation.

The conversion of nitrogen from one form to another in the nitrogen cycle is carried out primarily by Nitrogen Fixing Bacteria such as Azotobacter.

Jean Piaget was a cognitive psychologist who identified four stages of development: the sensorimotor stage from birth to 2 years, the preoperational stage from age 2 to age 7, the concrete operational stage from age 7 to 11, and the formal operational stage from age 11 to adult. He identified milestones that occur at each stage.

According to Piaget, the main task of the sensorimotor stage is for the child to learn the concept of object permanence, use senses and motor skills to understand the world.

High frequency sound attacks the tympanic memberane and makes it defective. 120 decibles is too high a pitch to be heard and therefore it impairs the hearing ability.