Schleiden and schwann believed that
a. organisms are the basic unit of life b. both cells and organisms are basic units of life
c. the questions of the basic unit of life are too abstract to answer
d. none of the above

New york city has 2,181 inhabitants per square mile. the state of alaska has 1.03 inhabitants per square mile. ecologists would say alaska has a low exponential growth population density birth rate carrying capacity

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

This is an active transport mechanism by which cells pump sodium and potassium ions against the concentration gradient