Answer:
I think its lipid
Explanation: I am taking the test right now for grad-point so tell me if i am wrong .
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Botanist
Biologist/Biological Scientist: A scientist who studies living organisms and living systems. Botanist: A scientist who studies plants. Chemical Ecologist: A scientist who studies chemicals in the interactions of living organisms. Chief Scientist: A scientist who leads other scientists in a particular research area.
Explanation:
1. cell membranes are partialy permeable, only allowing passage to some certain molecules.
2. diffusion is the movement of molecules across partially permeable membrane down concentration gradient.
3. the molecules are too big to pass through partially permeable membrane. the concentration of the molecule might be higher in the cell than in the solution/surroundings.
Answer:
Mechanical barriers — which include the skin , mucous membranes , and fluids such as tears and urine — physically block pathogens from entering the body. Chemical barriers — such as enzymes in sweat , saliva , and semen — kill pathogens on body surfaces.
