A river that comes from rain, glaicers etc would be a good example of fresh water rivers. Cause the water is coming from something that is most likely been unthouched by man or has been filterd and cleaned from minerals in the ground.
Air also affects evaporation,If a air pressure is high on the surface of a body of water,then the water will not evaporate easily.The pressure pushing down on the water makes its difficult for water to escape into the atmosphere as vapor... Temperature,of course,affects how quickly evaporation happens.
Crossing over. Parts of sister chromatids will sometimes switch places with the parallel part, resulting in a completely unique DNA sequence.
Answer:
This is an example of "Disruptive selection".
Explanation:
<em>Disruptive selection</em> occurs when <em>selective pressure</em> <em>favor homozygous</em>. In equilibrium, <em>the two alleles might be present or one of them might be lost</em>. If an environment has two extremes, then in these environments, both alleles are presented in homozygous.
The disruptive selection causes an <em>increase</em> in the two types of <em>extreme phenotypes over the intermediate forms</em>. Limits between one extreme and the other are frequently very sharped. Individuals belonging to one phenotype can not live in the same area as individuals belonging to the other phenotype, due to the traits differences between them, competition, or predation.
Populations show two favored extreme phenotypes and a few individuals in the middle. Individuals who survive best are the ones who have traits on the <u>extremes forms</u>. Individuals in <u>the middle</u> are not successful at survival or reproduction.
<em>Color</em> is very important when it comes to <em>camouflage</em>. Dark green caterpillars that live in dark foliage and light green caterpillars that live in light foliage can <em>hide from predators</em> more effectively and will live the longest. Intermediate colored green caterpillars that don't camouflage or blend into either will be eaten more quickly.