Physical Weathering in Nature. When water in a river or stream moves quickly, it can lift up rocks from the bottom of that body of water. When the rocks drop back down they bump into other rocks, and tiny pieces of the rocks can break apart. Many rock surfaces have small crevices on them.
Ex: Unloading.
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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Neither brain nor the Muscles
Answer:
B.
Explanation:
The movement of substances(ions and molecules) against their concentration gradient is called Active transport.Since these substances are moving against whew they are already in abundance,extra energy is needed for them to move against this gradient.Therefore,ATP.,oxygen is needed by the cells undergoing this transport process to transfer substances into the cells.
It is useful for entry of substances in plants e.g glucose,and for transport of materials in intestine in man
Na-K pumps, exocytosis,endocytosis are examples of this transport process.
It is inhibited by lack of oxygen,cyanide etc.