Answer:
Blood-brain barrier.
Explanation:
Blood brain barrier may be defined as the barrier between the blood capillaries and the component of the brain tissue. This blood brain barrier provide protection against the pathogens present in the blood.
The blood-brain barrier uses tight junctions that prevent the entry of microbes in the underlying tissue. The tight junctions allows only the entry of some selected particles and prevent the entry of other particles.
Thus, the correct option is (3).
Answer:
less than 7
Explanation:
If the rainwater is always acidic then its pH must be less than 7. pH is a scale which basically means negative log of [H+] or -log[H+] and the range that it covers is from 0 to 14. A substance can be acidic, basic or neutral based on the pH that it has. If the pH of a substance is less than 7 then it means the substance is acidic, if the pH of the substance is more than 7 then it means that the substance is alkaline while a pH of 7 indicates that the substance is neutral.
17.27 Ibs my brother told me this is confidence so probably