"you are installing solar collectors on the roof of your home to cut your use of the propane gas that heats both your hot water tank and the living spaces in your home. in doing so, you are using a(n) resource rather than a(n) resource._"

perpetual, unrenewable.

Explanation:

"You are installing solar collectors on the roof of your home to cut your use of the propane gas that heats both your hot water tank and the living spaces in your home. In doing so, you are using a perpetual resource rather than an unrenewable resource." Perpetual resources are those resources that cannot be depleted. Perpetual resources refer to wind energy, solar energy, and tidal energy. Installing solar collectors on the roof is the way to save on non-renewable resources like propane gas. Non-renewable resources are limited in quantity.

a. the moon was locked into orbit by the earths gravity as it was passing by and capture hypothesis i think