How many types of nucleotides are in dna, and how do they differ?

Which chemical equation is unbalanced? which chemical equation is unbalanced

Match the pollutants. 1. a chlorofluorocarbon smoke 2. a biodegradable organophosphate insecticide freon 3. particle pollution paint 4. hazardous waste monoxide 5. carbon is completely burned malathion 6. carbon is incompletely burned dioxide

The most famous fossil called archaeopteryx is which of the following? a dinosaur a fern a fish a bird