Logan chooses to study for an economics test instead of going hiking. The opportunity cost is .

Which organisims can cause diseases a. micro organisims b. multicellular organisnims c. both d. neither

When you can't determine who arrived at an intersection first, yield to the vehicle a. closest to you on the left b. closest to you on the right c. across from you d. with the largest wheelbase

What property does soil or rock need to be permeable? a.)young b.)old c.)non porous d.)porosity