<span>The immune system is the body's natural defense mechanism against organisms that can cause infection.There are three types of mechanisms:
1. Cellular :</span><span> refers to the recognition and/or killing of virus and virus-infected cells by leukocytes and the production of different soluble factors (cytokines) by these cells when stimulated by virus or virus-infected cells
</span><span>
2. Structural: </span>barriers and the immune system defend the body<span> against organisms that can cause infection. </span>Natural<span> barriers include the skin, mucous membranes, tears, earwax, mucus, and stomach acid.
3. Chemical: </span><span>Some of these include the low pH of the stomach, which inhibits the growth of pathogens; blood proteins that bind and disrupt bacterial cell membranes; and the process of urination, which flushes pathogens from the urinary tract.
</span><span>antibodies - chemical
tissues lining hollow organs - cellular
phagocytes - cellular
skin - structural
antigen - chemical
leukocytes - cellular</span>
The answer is whales. In the Antartic and Arctic regions, krills and whales are very abundant in numbers. Whales are number one consumer of krills in these regions. They can feed on a large swarm of krills when they feed. They also have less competition on these icy waters. They gain energy every time from eating them.
Answer:
The terms old world and the new world are used in the context of history and for the prime objective of differentiating the major ecozones found on the planet. This also helps in categorizing various species of plants and animals that originated in different places and times.
In terms of old and new, Old World signifies to Asia, Europe, and Africa, on the other hand, the New World signifies towards the Americas that comprise South America, North America, and Central America. The New World monkeys possess prehensile tails, while the Old World monkeys don't. This suggests that the prehensile tail originated in the monkeys found in the New World, primarily after the separation of the Americas from Asia and Africa.
Answer:
Explanation:The Photosystems are the functional centers of photosynthesis. The pigments, such as chlorophyll, in the photosystems absorb light energy, which excites electrons. These electrons are transferred to electron-accepting molecules, eventually producing ATP and NADPH.
