Answer:
<u>d. Transport proteins within the membrane serve as a tunnel for molecules to enter the cell.
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Explanation:
Solutes are typically moved across the cell through either passive or active transport. The cells, surrounded by a bilipid layer or plasma membrane is amphiphlic- its polar, hydrophilic lipid heads face outwards, while their non-polar hydrophobic lipid tails face inwards towards each other.
While lipid-soluble molecules move across the layer easily, it is also difficult for charged and also large molecules to move across its surface, into the cell. Transmembrane channels, <u>embedded within the membrane</u>, help to maintain selective permeability as transport proteins, pores and gated channels. Simple diffusion happens as a method of passive transport in cells through plasma membranes.
The solutes travel through the plasma membrane in the process of diffusion from regions of high concentration to regions of low concentration; this occurs without the use of energy. <u>Molecules moving against their concentration require active transport mechanism to cross the membrane</u>.
<u>ANSWER:</u>
Ogallala aquifer supplies "one-third of the irrigation water" in the United States.
<u>EXPLANATION:</u>
- The "Ogallala aquifer" is located in the "Great Plains of the United States" and therefore gives life to almost all fields of the US.
- The aquifer supplies water for one-third irrigation needs of the United States. The Ogallala is an underground reservoir and is very big in size and the agriculture production in the US is dependent on this aquifer.
- The aquifer is however depleting and water level in many areas has become very low.
- It is important for United States to protect and preserve this aquifer so that the agricultural production does not suffer.
It is false bc the mass of moon is less than 1/2 of earth, and earth is tinier than ANY STAR
Answer:
D
Explanation:
a statement that can be tested through a scientific investigation
