Climate change is usually negative because if it dramatic it could kill most of species.
The ileum contains villi that project into the lumen and increase the amount of surface area.
Villi are small finger-like structures that project into the lumen of the small intestine. Villi increase the surface area of the intestinal walls for easy and quick absorption of digested food with the addition of digestive secretions. Villi vary in length from about 0.5 to 1 mm. They are usually found in large numbers at the beginning of the small intestine and they reduce toward the end of the tract.
Comparing the physical features of the three types of skeletons
<u>Endoskeleton :</u>
Less Flexible than cartilage
<u>Exoskeleton :</u>
very rigid and hard
<u>Hydrostatic skeletons </u> :
Less rigid and very flexible
<h3>Physical difference of the types of skeletons </h3>
The endoskeleton is the internal skeleton present in vertebrates in the form of bones which enables the movement of animals while supporting the organs of the body to remain in position. they are less flexible when compared to cartilage. Exoskeletons are outer skeletons which protect organisms and also enables them to move freely. They are very rigid and hard.
Hence we can conclude that the comparison between the types of skeletons are as listed above.
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The difference between them is that they are active in fighting infection.
Plasma cells are active in defense during the first exposure to invaders like viruses or bacteria producing antibodies. Memory cells last longer and make a copy of the invaders. This allows an extremely rapid defense later in case of a second exposure.