Answer:
The correct answer is option d. "Its conformation will change when both an ion and a small molecule bind to it".
Explanation:
The secondary active transport is a form of active transport at which a ion (typically Na+ or H+) is transferred down its electrochemical gradient to the uphill movement of another molecule. Secondary active transport takes place by the conjunctive work of membrane-bound proteins and sodium–potassium pumps. During secondary active transport, both of these proteins change its conformation when an ion and a small molecule bind to it. This change in conformation makes possible that the ions and the small molecules pass through the membrane.
The astronomical unit, otherwise known as AU is used to measure long distances in the universe.
In photosynthesis oxygen is released to the atmosphere which means the third option is correct.
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