Congo red is called a “ph indicator”. what does this mean?

A pH indicator is able to tell what level of pH the substance is at. It can tell how acidic a substance is. If a substance has more hydrogen ions than hydroxide ions then it is acidic. If it has more hydroxide ions that hydrogen ions it is an akaline. the acidic scale is from 0 to 14. lower numbers means more acidic and higher numbers means it is an alkaline.

Explanation:

pH stands for potential Hydrogen.

[content deleted] - user123802726recklesschicken

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation: