Please help this is science and about carbon cycle

What happens when the cell copies its chromosomes

Which set of characteristics best describes sedimentary rock? a) largest type of rock, made of organic matter, hardest type of rock b) often contains layers, forms near sources of water, contains fossils c) least abundant type of rock, made of other rocks, made mostly of minerals d) most abundant type in earth's crust, made of magma/lava, contains no fossils

If a strand of dna has 35% thymine. what is the percentage of cytosine, adenine, guanine?