A decline in sensory responsiveness that occurs when a stimulus is unchanging or repetitive is called .

Sensory Adaption

Explanation:

Stimuli, both external and internal, are sensed with the help of sensory receptors. These sensory receptors sense the change in internal or external conditions called stimuli and send the information to the central nervous system. The sensory information is processed and interpreted in the central nervous system which in turn makes a person aware of the sensed stimuli.

However, the constant presence of the same stimulus does not trigger the firing of the action potential as it occurred during the first few encounters. This is called sensory adaption. For example, chirping of birds is apparent when a person enters the countryside but becomes less apparent after a few days due to sensory adaption of ears.

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation: