Because as trials go on scientists discover more information and alter the theories and that is why they are referred to as a "theory" instead of a scientific "law"
The answer is serotonin. Serotonin is a significant chemical neurotransmitter in the human body. Serotonin that is used in the brain must be made within it. It is believed that serotonin can touch mood and social performance, hunger and ingestion, slumber, reminiscence and sensual desire and purpose.
Answer:
Water erosion can contribute to pollution.
Explanation:
Remember that pollution refers to the introduction of contaminants in natural environments causing negative changes in the ecosystem.
Water erosion is possible because of the sediments that carries and erode soil surface. Also, it can contribute to water contaminations because of the different types of sediments can carry, finally causing pollution.
<u>Answer:</u>
<em>It is not true to say that common ancestors occurs only within a single species rather two species with similar traits might have a common ancestor. </em>
<u>Explanation:</u>
If the ancestor is same for both the species then it is said that both the species are closely related and share common ancestor with similar evolutionary relationship.
Phylogenetic tree are drawn and studies are done to understand the ancestor of a species. The evolution has occurred from the ancestor to the new species formed.
