17. due to human demand because of its importance to life, the earth's most precious resource is a. oil. b. freshwater. c. saltwater. d. soil.

I would say B .Fresh water.

Because we need to have fresh water to survive ,water without the salt, that causes dehydration. So C. would be ruled out. Also fresh water( rain water) is needed to grow crops, without it soil wouldn't be up to par for farming, so that rules out D.  Oil, to us is only valuable because of its place in our economy. We need it to fuel vehicles (etc.) Oil is more of a money thing in my opinion so I would rule that out too...for the record this is just off the top of y head. Im not sure if its correct

21 stacks

step-by-step explanation:

divide 630/30

21 stacks

enjoy!

kelp are large brown algae that live in cool, relatively shallow waters close to the shore. they grow in dense groupings much like a forest on land. these underwater towers of kelp provide food and shelter for thousands of fish, invertebrates, and marine mammal species.

e) all of the above