Answer:
A
Explanation:
Reptiles arose about 310–320 million years ago during the Carboniferous period.
The cell is considered to be the most basic living unit.
Answer:
Details about DNA are given in the explanation section. Hope it will be helpful for you.
Explanation:
DNA, or deoxyribonucleic acid, is the hereditary element in humans and almost all other organisms. Nearly every cell in a person’s body has the same type of DNA. Most DNA is found in the cell nucleus (nuclear DNA), but a small quantity of DNA can also be found in the mitochondria (mitochondrial DNA or mtDNA).
The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). Human DNA consists of about 3 billion bases, and more than 99 percent of those bases are the same type in all people.
DNA bases pair up with each other, A with T and C with G, to form units that are called base pairs. Each base is also attached to a sugar molecule and a phosphate molecule. A base, sugar, and phosphate are called a nucleotide. Nucleotides are arranged in two long strands that form a spiral called a double helix.
A valuable feature of DNA is that it can replicate, or make copies of itself. Each strand of DNA in the double helix can serve as a pattern for duplicating the sequence of bases.
Four haploid cells are produced by the process of meiosis. The correct answer is D.
