Base your answers to question 8 on the information below and on your knowledge of biology. Evolution leads to changes in how frequently
certain traits appear in a population. 8) Describe how the process of
natural selection can result in an increase in frequencies of certain traits
found in a population *

Natural selection refers the effect of selection pressure on the frequency of allele in the population.

Generally,natural selection increases the chances that  certain allele will survive for long period of time, and therefore the chances of successive reproduction. Therefore organisms with these alleles with higher chances of reproduction have high selective advantages, and therefore better adapted to withstand the selective pressure and therefore undergo directional selection within the organisms in the population.

Consequently, they are better reproduced, and thus well populated.The r frequency of their traits is well  expressed  from generation to generation, and therefore naturally selected, and evolve over long period.

i dont know this but ask your teacher for !

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.