Answer: Directional Selection.
Explanation: Earlier the ancestors of the giraffe had shorter neck as compared to the giraffe of the present time.
They were not able to access the plants that lied at a higher height.They was some changes in the phenotype of the giraffe in which the giraffe has long necks to access the plants at height.
In directional selection the extreme form is preferred over other traits. Example: The long neck giraffe were selected over short neck.
Answer:
The human heart is a pump. It pumps blood around the body at different speeds and at different pressures according go the body's needs. It can do this because the wall of the heart is made from cardiac muscle. Blood is moved through the heart by a series of contractions and relaxations of cardiac muscle in the walls of the four chambers.
Answer:
<u>Louis Pasteur</u>
Explanation:
Although louis was a great scientist who made contributions to the cell theory postulating that cells come from preexisting cells, he was a renowned and father of microbiology. He proved that diseases are caused by microorganisms, developed the first vaccine and provided logical ground knowledge on fermentation and brewing.