Stores nutrients and transfers them to the embryo during germination
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.
Answer: Polarity of a Water Molecule
Explanation: Water (H2O) is polar because of the bent shape of the molecule. The shape means most of the negative charge from the oxygen on side of the molecule and the positive charge of the hydrogen atoms is on the other side of the molecule. This is an example of polar covalent chemical bonding.
In mammals urine is expelled through the urethra which is part of the excretory system in unicellular organisms waste products are discharged directly through the surface of the cell
It is referring to natural selection