They are useful because of the way they process and digest food. They apply their enzymes externally and then absorb smaller mollecules. This process releases things like CO2 or creates alcohols, and this has historically been used in making drinks like beer or foods like bread and cheese.
Two species of sea urchins live practically side-by-side in sandy bottoms. The two species appear to have the same diet: drift seaweeds and other bits of organic matter. They can live in the same environment without competing.
As it compels them to live in the same environmental surroundings so the characteristics of living nature also get developed as their current following situation that's helping them to get the same food & habitat.
The very primitive organism is the oldest because, over time, organisms gradually evolved into more complex organisms. First came the primitive organism, then it evolved into the more complex one, or the younger fossil.
From studies and research, I believe the proper question would be:
"How do the animals satisfy their need for water?" or "How long do the animals live?"
Explanation 1:
When studying the desert, asking "Can you buy the animals in pet stores?" is not going to help you find information about the desert because it is not a question to get information about the desert, only information if you just buy it at your local pet shop.
Explanation 2:
Asking "How many offspring do the animals have?" does help us learn about animals, but we are trying to find information on the structure of the desert in which the animals live in. We are not looking for how many children the animals will have because it doesn't fully relate to the question we would be asking.
Side Note: Offsprings mean children.
<em>Hope this helps!</em>
<em> ~Hocus Pocus</em>
Explanation:
The sun heats the air leading to warm air. the warm air rises thus makes the cooler air from the surroundings to replace it. This leads to creating wind . This same process applies for ocean currents.
The sun heats water which make warm water come to the surface of the ocean thus replacing it with cooler water leading to ocean currents.