The Cambrian explosion was a period at the Pre-Cambrian boundary of the geologic time scale at 542 Ma. At this boundary, the fossil record shows that animals suddenly appeared in a dramatic radiation of life. A radiation is the relatively rapid development of new types of organisms that derive from a common ancestor. The Cambrian explosion is important because it marks the origination of all major animal groups called phyla.
(15) Label 1 is D
(16) Label 2 is A
(17) Label 3 is B
(18) Label 4 is C
<span>Both protexts the organisms' organelles which are inside the cell.
Animal Cell: Cell Membrane
Plant Cell: Cell Wall
Cell
wall is present only in plants, it is not found in all organisms.
Compared to the cell membrane, a cell wall is thick and has a rigid
structure. You can see it in a light microscope, because it is visible.
It serves as the protective cover that surrounds the plasma membrane in a
plant cell. Cell membrane is composed of lipids. Cell walls can be made
up of cellulose or peptidoglycan or chitin.<span> </span></span>
