Answer:
Blood Brain Barrier(BBB)
Explanation:
This is a biological interface of special endothelial cells of astrocytes, pericytes , capillaries, neurons and other structures, acting as a physical barrier or gate separating the Central Nervous system from the peripheral blood circulations. Thus it formed a tight junction serving as a physical barrier to selectively regulate the entrance of substances from the cerebral blood flow into the brain, therefore maintaining homeostasis of the brain.
From above any substances absorbed into the blood stream irrespective of the mode of entry are transported through the BBB, and are selectively regulated to enter the brain cells by the BBB's interactions with the blood vessels, hormones etc.
Basically it allows the passage of nutrients, a few drug, hormones and resists certain toxins and pathogens for the brain homeostasis.
So they can breatheso they can breatheso they can breathe<span>so they can breathe
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Animal body is made of four different types of tissues.
Epithelial Tissue
Muscle Tissue
Connective Tissue
Nerve Tissue
Plant structure is different from the animal skeletal structure. A plant tissue is different from those in animals. Plant tissues are basically divided into two: Meristematic tissue and Permanent tissue.
Genes are what code for those things
It would be all if u can pick that but if not it depends on what animal the he question is talking about
