Hello!
We know that the movement of molecules from an area of low concentration to high concentration. This movement is <em>against</em> the concentration gradient and thus requires the use of adenosine triphosphate (ATP) to successfully move. This process is the opposite of diffusion, which requires the use of no energy because it moves materials <em>DOWN</em> the concentration gradient.
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Answer:
The Retina
Explanation:
The photoreceptors lie at the back of the retina
The correct answer should be the endocrine system.
Hormones are secreted by endocrine glands in endocrine systems. Opposite of this would be the exocrine system consisting of exocrine glands.
I believe the answer is heterotrophic
