They need to cope with changing seasons and be able to withstand cold winters and hot summers
Answer:
D
Explanation:
Absolute age is defined as the numeric age of fossils.
To identify the absolute age of a fossil, the amount of certain radioactive elements in the rock are measured. When fossils are formed in the rocks, a small amounts of radioactive elements is included in it. The process to identify age of fossil using radioactive elements is known radiometric dating. So, radioactive isotope and its decay product gives absolute age of fossils.
Hence, the correct answer is "D".
20 is the Number of Neutrons of potassium.
The buffer systems functioning in blood plasma include plasma proteins, phosphate, and bicarbonate and carbonic acid buffers. The kidneys help control acid-base balance by excreting hydrogen ions and generating bicarbonate that helps maintain blood plasma pH within a normal range.