Answer:
Option B
The plicae circulares, villi, and microvilli
Explanation:
The plicae circulares are the folds of mucous membrane on the inside of the small intestine. They are covered with tiny hair-like structures called the villi, and microvilli. The purpose of those folds is to increase the surface area for the absorption of food nutrients to take place in the small intestine before the food finally moves on to the large intestine for excretion.
The tiny hair-like projections (villi, and microvilli) further increase the surface area available for nutrient absorption by providing extra surfaces in which the nutrients can diffuse into the small intestine through.
This makes option B correct.
In the cell, energetically unfavorable reactions are often coupled with favorable ones, such that the new overall reaction is favorable.
C-Photosynthesis by producers
Halley's Comet is the most well-known comet. It's a "periodic" comet that comes close to Earth once in 75 years, allowing a person to see it twice in his or her lifetime. It was last seen on Earth in 1986, and it is expected to appear in the year 2061.
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An INHIBITORY Signal is sent between neurons when (A)Na+ rushes into the neuron.
Explanation:
- When one spot of membrane supports an action potential, lots of \text {Na}^+Na+start text, N, a, end text, start superscript, plus, end superscript ions hurry into the cell by that spot.
- These ions radiated out sideways into the cell and can depolarize a nearby spot of membrane, stimulating the hole of voltage-gated sodium channels and causing the nearby spot to support its action potential.
- The action potential can only move in one direction – from the cell body towards the axon terminal – because a spot of membrane that has just experienced one action potential is in a “refractory period” and cannot withstand another.
