What is an ecosystem that normally functions without human tending?

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

In which situations is the principle of cross-cutting relationship useful in determining relative age?

Acceleration is a direct result of a.) balanced forces b.) unbalanced forces c.) gravity d.) velocity