These preparations are called Vaccines. A vaccine is a biological preparation that provides active acquired immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing micro-organism and is often made from weakened or killed forms of the microbe, its toxins or one of its surface proteins.
The question is asking to states on how i earth's early lang environment different than today's land environment and base on my research, I would say that in the past centuries or early ages, the Earth's land environment are compost of tree and plants and the air is still fresh. I hope you are satisfied with my answer and feel free too ask for more
An example of a person is not a bad guy and I don’t want him going back
C are you dum
Yes this is so easy give me brainiest