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:
The antibodies produced by a vaccine only fight specific antigens.
Explanation:
Antibodies only bind to specific antigen during an immune reaction. The introduction of foreign substance in the body stimulate the B-cells to produce antibodies that fight against infections. Only specific antibodies are produced following antigen presenting cells that bind to antigens. They capture and display the antigens to the antibodies.
Answer:
Plants can synthesize all twenty amino acids.
Explanation:
