Name classification of matter used in 1800

In the 1800s the matter was divided into two categories which are:

1) Organic matter

2) Inorganic matter

The difference between them was that organic referred to living matter which have life in them as opposed to inorganic matters which are lifeless or are of geological nature such as rocks, mountains, minerals etc.

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:

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