19. What does top Soil Contain?

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

Plz ! what does it mean for an allele to be dominant?

What will happen if two of the base pairs of the stand of the dna are switched