The keystone species is the one at the bottom of the pyramid, if we look at it like a pyramid. If the grass dies, then the deer cannot get food and die, and the predator cannot eat and dies, and the whole ecosystem can fall apart.
Answer:
The <u>nuclear envelope</u> is composed of two concentric lipid bilayer membranes separated by an intermembrane space of about 20-40 nm. The outer membrane is continuous in many places with the rough endoplasmic reticulum. Like the rough ER the outer membrane of the nuclear envelope is dotted with ribosomes.
Red Blood Cell: Binds and carries Oxygen
White Blood cell: Fights pathogens that can cause sickness
Platelet: Helps in the healing of cuts and wounds
Plasma: Contains the liquid portion of blood
