Explanation:
One of a number of alternative forms of the same gene occupying a given position, or locus, on a chromosome is allele.
Answer:
two, phospholipids, non polar, tails, polar, heads.
Explanation:
This is just basically illustrating one of the components of the lipid bilayer memebrane. The membrane is made up of two lipid layers with the polar head groups facing either the cytosol or the outer surroundings while the non polar tails facing each other. Such that this bilayer act as a barrier between the cytosol of the cell/organelle eg endoplasmic reticulum and the outer surroundings.
A. <span>Exposure to an antigen
Exposure to viruses and antigens led to the foundation of modern vaccination. Vaccination introduces an antigenic material that helps the ability of the immune system to adapt a specific pathogen, therefore leading to a long-term immunity.</span>
We need blood because it carries oxygen and helps us sustain life. The organ that pushes blood through the body is the heart.
The answer is Permian-Triassic extinction.
The Permian-Triassic extinction was 252 million years ago. It is known as The Great Dying because about 95% of all species died out due to environmental changes (volcanic eruptions, dry climate, melting of ice sheets, etc). This is also the only event in which many insect species wiped out.
