Spraying insects with a pesticide ddt causes some pesticide resistance in insect populations. The changes that occur in the insect population are related to a pattern in genetic inheritance. Repeated spraying kills many insects; however, more frequent spraying and higher concentrations fail to kill insects. In this environment, the spaying of insects appears to act as SELECT ONE:
A. BIOLOGICAL FACTOR
B. GROWTH INHIBITOR
C. AN AGENT OF SELECTIVE PRESSURE
D. AN AGENT TO ELIMINATE OLD WEAK INSECTS

D. AN AGENT TO ELIMINATE OLD WEAK INSECTS

Explanation

Because when older bugs get poisoned they have a less of a chance to survive because their already old and crippled.

But using cinnamon is a more effective way of killing bugs and ants and it does not  harm children or other house hold animals that you may have.

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:

b exhibiting favoritism toward the kikuyu people.