A pollutant is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource.
<span>The answer is a certain required chemicals must be actively
transported. Blood brain barrier is a
selective membrane that separates blood circulating from the brain and the
fluid of extracellular in the central nervous system. This is also called a
filtering mechanism, the capillaries that carry blood to the brain and spinal
cord tissue blocking the path way of the certain substance.</span>
The tissue is identified as skeletal muscle tissues. These muscle tissues are long, cylindrical, striated, multi nucleate cells and are arranged parallel to each other
Skeletal muscle is one of three major muscle types other than the cardiac and smooth muscle. Most skeletal muscles are attached to bones by bundles of collagen fibers known as tendons.
Answer:
1.) The two gametes found in humans are the sperm and the ova.
2.) Variation, in biology, any difference between cells, individual organisms, or groups of organisms of any species caused either by genetic differences (genotypic variation) or by the effect of environmental factors on the expression of the genetic potentials (phenotypic variation).
3.) Because the alleles that the mother and the father carry are mixed together in the offspring.
4.) Because it only introduces genetic variation into the population if a random mutation in the organism's DNA is passed on to the offspring.
Please this is all I can answer
I think its called a polar molecule
