Which nitrogenous bases are considered pyrimidines?

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

Explain how light energy is turned into chemical energy? ! due tomorrow!

Why should organisms reproduce more offspring than will survive? select all that apply.