Answer:
The correct option is: e. molecules move across the plasma membrane against their concentration gradient
Explanation:
Active transport refers to the <u>movement of the particles or molecules from higher concentration to lower concentration, across the plasma membrane of a cell.</u> This transport requires cellular energy as the movement of the molecules is <u>against the concentration gradient</u>.
Active transport can be divided into primary and secondary active transport.
<span>The correct statement is letter C. All arteries except the pulmonary artery carry oxygen-rich blood. Most arteries are responsible for the delivery of oxygen and nutrients to all cells and the pulmonary veins are the one who transfer oxygenated blood from the lungs to the heart.</span>
The greenhouse effect is a natural process that warms the Earth's surface. When the Sun's energy reaches the Earth's atmosphere, some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases. The absorbed energy warms the atmosphere and the surface of the Earth.
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