Why didn't alexander fleming see the mold spore fall in the petri dish

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

How does photosynthesis show the conservation of mass and energy?

The relationship between intron and exon