Explain how bacteria don’t over run the earth

Competition and lack of nutrition are probably the main reasons – just like with any organisms, and to a much lesser extent inhospitable environments And like myth said, other species are capable of defending themselves.  For example, some eukaryotic unicellular organisms eat bacteria, and bacteria compete for nutrients against one another, as well as against other microorganisms living in the same ecological . For example, many molds secrete substances that kill or inhibit bacterial growth. Even  if there wasn’t any direct competition by other organisms, bacteria couldn’t "take over the world", if by that we mean that they’d cause the extinction of all other life forms and would be the sole survivors on this planet: there’d always be lots of habitats that are inhabitable for bacteria – mainly very dry (or cold) places, where vegetative bacteria survive only when living as symbionts or parasites on multicellular organisms that can survive there. So in other words, even if bacteria could rid the world of other living creatures, it would be against their best interests in many cases, and thus natural selection wouldn’t direct their evolution that way.

the supermassive black hole is in the middle of the galaxy.

you know that this symptom is misleading and quite often is related to: heart attack

a heart attack is a condition that occurs when the blood flow that transports oxygen to the heart muscle is damaged or cut off completely. the coronary arteries that supply the heart muscle with blood flow can be blocked by the accumulation of plaque. also, when the plaque within the heart artery breaks, it creates blood clot that can also hinder the blood flow. men that are over 45years of age and women that are over 55years of age are at risk of having a heart attack. the symptoms of a heart attack include chest discomfort, chest pain, coughing, and shortness of breath.