Answer:
b. a semi-permeable double layer of phospholipids that have hydrophilic heads and hydrophobic tails
Explanation:
B is correct as the cell membrane is selectively semi-permeable. It is selectively semi-permeable because this quality allows it to control what can and can't enter the cell, and how it does so.
The cell membrane also has a phospholipid bi-layer comprised of a double layer of phospholipids which have hydrophilic head and hydrophobic tails. This is because the heads are made of phosphate and are polar and are therefore attracted to water (hydrophilic), while the tails are made of lipids (i.e. fats, oils) which do not mix with water and are therefore hydrophobic.
The properties of each phospholipid is also why they form the double layer structure, the hydrophilic heads naturally face outwards into the water and protect the hydrophobic tails on the inside.
Hope this helped!
Answer: No
According to <u><em>BBC</em></u>, Human activities such as harvesting plants and hunting animals can unbalance the flows and cycles within those [SMALL SCALE ECOSYSTEMS ]ecosystems. Tree-felling may lead to soil erosion and a loss of habitat. Lack of shade and moisture in the soil can result in desertification.
According to <u><em>National Geographic</em></u>, Humans impact the physical environment in many ways: overpopulation, pollution, burning fossil fuels, and deforestation. Changes like these have triggered climate change, soil erosion, poor air quality, and undrinkable water.
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As water molecules from plant leaves evaporate, they attract the water molecules that are still present in the plant, aiding in the movement of water from the roots up through the stems. The water in a plant is transported from the bottom to the top by the combined effects of transpiration and capillary action.
- Water molecules ascend up the cellulose tubes from the roots to the leaves because they tend to cling together (cohesion) and stick to the walls of tubes (adhesion). The water from the leaves then evaporates, aiding in the root system's ability to absorb additional water. We call this mechanism capillary action.
- Water and minerals travel upward from the roots through the xylem due to a negative water potential gradient created by the evaporation of mesophyll cells in the leaves. Small perforations between vessel elements must be made to reduce gas bubbles in the xylem since they can obstruct water flow in the plant.
Learn more about Xylem here:
brainly.com/question/17881747
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