The two differences you see when comparing the four chambers of the heart is that the arteries have a thicker wall and veins have thin walls and that the arteries carry oxygenated blood away from the heart which means they get more pressure than veins.
Answer: The study of plant varieties.
Explanation:
This question relates to the studies that Gregor Mendel, founder of modern genetics, performed at the University of Vienna.
Experimenting on pea plants, Gregor Mendel was able to establish a lot of the rules of heredity that we know today even though his research was not fully appreciated or understood during his own life.
He credited the study of plant varieties to have been most crucial to his final analysis because farmers had been crossbreeding varieties for millennia to bring about better traits in plants.
Explanation:
Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules within all life-forms on Earth. Nucleotides are obtained in the diet and are also synthesized from common nutrients by the liver.
Nucleotides are composed of three subunit molecules: a nucleobase, a five-carbon sugar (ribose or deoxyribose), and a phosphate group consisting of one to three phosphates. The four nucleobases in DNA are guanine, adenine, cytosine and thymine; in RNA, uracil is used in place of thymine.
<em>Hope</em><em> this</em><em> helps</em><em> please</em><em> like</em><em> and</em><em> mark</em><em> as</em><em> brainliest</em><em> </em><em /><em />
Answer:
The correct option is <u><em>A. they evolved from land mammals.</em></u>
Explanation:
The process of evolution explains how closely one organism is to another based on their common ancestors. Scientists believe that those organisms which show many similarities in their structures or functions might have evolved from a common ancestor in the past.
As in the above-mentioned question, scientists have observed that cetaceans lack gills and breath air, this is a property of land mammals. The cetaceans have fin bones which are similar to the limb bones. As limb bones are present in land mammals, hence they cetaceans and land mammals might have common ancestors in the past.
