What is the whole number placed in front of a molcular formula in a chemical equation Called

This rapid change in species that rarely leaves behind fossil evidence is referred to as

Which of the following determines the specificity of a dna probe? a. type of radiation b. level of enzymatic activity c. number of neutrons d. complementary base pairing

Which of the following molecules could pass through the plasma membrane by simple diffusion? a. na+ ions b. glucose c. amino acids d. carbon dioxide