The immune system.
The immune system acts as a defense system of the body. It fights against bacteria, viruses and any other disease causing pathogens. Some chemicals can weaken the immune system and make them vulnerable.
Limestone is composed largely of the minerals calcite or aragonite. Some limestones do not consist of grains and are formed by the chemical precipitation of calcite or aragonite. This is how limestone can be classified as chemical.
Answer:
The answer is Paleozoic Era
The Answer is C. DNA
Our DNA is responsible to carriy out our genetic information which located in our cell nucleus.
The Scientist previously thought the molecul of inheritance is composed of Lipids (some sort of proteins)
As for RNA, it only carried out genetic information in a couple of viruses. Even most viruses use DNa to carry out its genetic information
