3A- Negative feedback occurs when some function of the output of a system, process, or mechanism is fed back in a manner that tends to reduce the fluctuations in the output, whether caused by changes in the input or by other disturbances.
3B- Negative feedback loops are used to maintain homeostasis and achieve the set point within a system. Negative feedback loops are characterized by their ability to either increase or decrease a stimulus, inhibiting the ability of the stimulus to continue as it did prior to sensing of the receptor.
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Answer:
Deep zone, surface zone and transition zone.
Explanation:
Open sea zone is the area of the coastal areas above the sea bed and cover the continental shelf where large Marine organism are present and there is enough sunlight algae organism use to photosynthesize and produce food for the Marine organisms by converting carbondioxide and water into carbohydrates.
The zone stretches from the surface , to the middle and depth of 200 m.
The surface zone is the area where light penetrates most , the transition stretches from the surface zone downward, in this zone light penetrates bit not as much as surface zone and in the deep zone, it stretches from the transition zone downward to a depth of 200 meters and don't have enough light penetration compare to surface and transition.
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.