Coral reefs are here in our world, and we have a duty to protect them. Things like fertilizers and pesticides are the things that are harming them, which comes from humans and causes the reefs to get sick.
If that answer isn't enough, then maybe this one will help?
Over fishing occurs when humans fish more than they should in a coral reef and eventually the fish can no longer thrive, and they simply disappear. Not only is this bad for the reef, because it too will then die, but them humans will no longer have that source of fish, which is what man groups of people and fisher man need to keep their businesses running and is where people get a main source of food. Fishing is what keeps many people alive and keeps smaller fishing villages running, and without it, they cannot survive either. <span />
A pulsar is a neutron star that gives off pulses of radio waves. The Crab Nebula, which is one of millions of gas and dust clouds in space, was found to house a pulsar in the system as is the central object present. Astronomers observing the nebula noticed that it released pulses of radiation that span the electromagnetic spectrum, pulsing radio, gamma and xrays.
Deserts are dry and infertile, so not my plants and living things are able to live and grow there.
As temperature increases, density decreases
As depth increases, density increases
As latitude increases, density decreases
As salinity increases, density increases