What is the function of our ecosystem? Environmental Issues: Select the best answer from the choices provided.
A. It shields the Earth from the sun's UV rays.
B. It breaks down and absorbs pollution.
C. It increases oxygen in the atmosphere.
D. It increases temperature in the summer and decreases temperature in the winter.

answer; first blank(1); 30% two(2); salmonella; i believe this is correct; //good luck;

"choosing is refusing" means individuals face an opportunity cost with each decision they make. economists state that every decision involves trade-offs. opportunity cost is the least desirable alternative given up as a result of a decision.