Karen is NOT correct. This is because the sun's energy is a renewable resource. This means that its use is sustainable hence it is a substance of economic value that can be replaced or replenished in the same or less amount of time as it takes to draw the supply down. Though the sun is a finite resource, it cannot be depleted within human timescale.
The skin color of fish is used to demystify human skin pigmentation. As revealed by studies, a fish skin color is influenced by both genetics and the environment. For example, the skin pigmentation of fish exposed to a more saline environment and fed saltier food is different compared to fish exposed to a lower concentration of salt. Based on years of studying fish skin color, it can be deduced that the variety of human skin pigment is also influenced by genetics plus the environment.
True, depending on which isotope. some Isotopes are deemed extremely unstable and cannot be used for nuclear fuel. however, most are usable