Geologic Time Scale.Scientists decide when an era begins<span> and </span>ends<span>, due </span>to<span> mass extinction. ...</span>Scientists determine<span> when drastic changes </span>are<span> made by the fossil record, which shows earths past organisms that have become extinct.</span>
Answer:
The snake belong in Animal
Explanation:
Answer:
According to this hypothesis, viruses evolved early in Earth's history from fundamental replicative molecules that formed in the “primordial soup” as the planet began cooling. These molecules also led to the evolution of cellular organisms—the viral hosts—either in parallel or at a later stage of evolution.
That would have been 3 or so billion years ago, early in earths history.
Answer:
Red blood cells.
Explanation:
Our blood is made up of blood cells and plasma which is an aqueous fluid. Blood type is determined by the identifiers presence and absence which is present on the surface of red blood cells. These identifiers are known as antigens which helps in the immune system to identify its own red blood cell types.
There are 4 types of blood type:
A, B, O, and AB. These blood types are determined with the help of the antigen which is present on the surface of the blood cell and antibodies which is present in the plasma.
