Scientists developed the time scale by studying rock layers and fossils world wide.
Radioactive dating helped determine the absolute divisions in the time scale. so mass extinction help because there is more to study
I think it’s 2 , 3, and 4
Hope this helps!
Answer:
Blood plasma:
55% composition of blood contains blood plasma. The plasma contains various proteins and coagulating factors. This mainly include the fluid portion of the blood. Plasma is a straw colored liquid that contains antibodies as well as serum.
Formed elements:
45% composition of blood contains formed element. The formed elements contain RBCs, WBCs and platelets. This mainly include the cells portion of the blood. Formed elements is red color or no color depending on the pigment present in the cells of formed element.
<span> Acids like acid rain that hits rocks and plants and affects them are examples of chemical weathering. Roots growing in cracks in rocks can also be considered to be physical weathering. </span>