The subscript; the number at the bottom right of the symbol
Water pressure and temperature varies at different depths of the ocean.
Fish poop.
Tropical white beaches get their pearly white color from the excrement of fish far off of the coast which eat coral and other things that reside on the ocean floor. When they eat they swallow some sand into their mouths as well, and process it with the food they just ate. Their stomachs can't really digest the sand, tiny minute rocks essentially, and thus turn their color white. Or the rock forming the sand can be naturally pigmented a whitish tone as well.
<span>repressors as well as by transcriptional activators.</span>
This statement is true. Early land animals indeed had gills as well as lungs. It is generally known that amphibians breathe through their skin, like how the lungs needed the skin for its respiratory. Fish have gills for breathing while mammals do have their nasal cavity and lungs for their gas exchange.