Contaminants that enter the groundwater may remain there for decades

Some birds look for food near cattle and other livestock. the movement of the cattle churns up the ground, making insects available to the birds. the cattle appear to be unaffected by the presence of the birds. what kind of relationship exists between the birds and the cattle? o a. parasitism o b. commensalism o c. predation o d. mutualism

Which macromolecule catalyzes chemical reactions this be considered enzyme chemical reactions thus he considering enzymes

What does the positioning of transcription factors determine?