D. <span>controlled
is the right answer because a</span><span>n </span>experiment<span> in which an observer tests a hypothesis by looking for changes carried by alterations to a variable.</span>
Answer:
Active transport requires energy from ATP while facilitated diffusion does not
Explanation:
Active transport and facilitated diffusion with the use of channel and carrier proteins are both ways by which ions, polar and large molecules cross a selectively permeable membrane.
The major difference is that; Active transport transport these particles from a low to high concentration, which is against concentration gradient and hence, energy is required to perform the task
Facilitated diffusion transport from a high to low concentration, which is through a concentration gradient and hence, no energy is required to perform the task.
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Answer:</h2>
<h3>1. Hepatitis B </h3><h3>2. Levels of circulating antibodies against a certain antigen.</h3>
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Explanation:</h2>
<h3>Hope its help</h3>
Because we have carbon in the ground in the air and every were else