]which of these statements is correct about the theory of adaptation?

Adaptations are the result of evolution in different living organisms. This process occurs amazingly through gene mutation but it takes a very long period in time. Adaptation processes occur to help species survive and thrive in the ecological balance of life. Structural adaptations are physical features of an organism that adapted through time. An example of this are the bills of a bird and the fur of bears that they generally need for their survival; birds for hunting, and bears to protect them from low climate areas.

Evolution by adaptation has three results:
Adaptation
By-product
Noise

You didn't provide us with any sentences? The theory of adaptation generally states that when we have organisms over a longer period of time in a certain area, they will continuously adapt to the limitations and challenges found in their environment. For that reason, they will be better and better over time in how they handle their environment. 

Yes yes yes very good

oxygen is the first element in group 16 (via) of the periodic table. the periodic table is a chart that shows how chemical elements are related to each other. the elements in group 16 are said to belong to the chalcogen family. other elements in this group include  sulfur, selenium, tellurium,  and  polonium.  the name chalcogen comes from the greek word  chalkos,  meaning "ore." the first two members of the family, oxygen and sulfur, are found in most ores.

oxygen is by far the most abundant element in the earth's crust. nearly half of all the atoms in the earth are oxygen atoms. oxygen also makes up about one-fifth of the earth's atmosphere. nearly 90 percent of the weight of the oceans is due to oxygen. in addition, oxygen is thought to be the third most abundant element in the universe and in the solar system.

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