This is because not all genes are expressed at the same time, so not all the proteins are present at a certain moment. The mechanisms that cell uses to control gene expression are called regulation of the gene expression. Thanks to regulation of the genes, cells have the ability to increase or decrease the production of specific gene products such as proteins. This property is important for the adaptability of an organism because it allows the cell to express protein when needed.
Genetic drift occurs when there is no random mating across a population. This causes a change in allelic frequency due to a random sampling of the population.
As the aboriginal population explored the earth, a small part of the population became geographically isolated either due to continental drift and climate changes. As the isolated population grew bigger, they established their own gene pool. This resulted a change in genotypic frequencies from that of the aboriginal population.
Answer:
#IN GIRLS
* adolsence
* menstruation
#IN BOYS
* penis strts turning big
*beard starts coming of face
Answer:
The correct answer is option A. "The contents of blood come into closer contact with tissues in a closed system than an open system".
Explanation:
In a closed circulatory system, the blood has an specific path, circulating from arteries to veins and to smaller blood vessels throughout the body. This is in contrast with open circulatory systems at which the blood is not contained in arteries or veins but it suffuses the body. A closed circulatory system have many advantages over open circulatory system, however in a closed circulatory system the contents of blood are not into closer contact with tissues in than an open system. Actually, in an open circulatory system the blood is in closer contact with tissues.
He could race multiple cars with different weight added on them and do multiple races (just to be sure) and see if his theory was correct, if not he should right down what he has learned from his experience! :D
-You'll never learn if u don't try ;)
