The skeletal system<span> performs vital </span>functions<span>— support, movement, protection, blood cell production, calcium storage and endocrine regulation — that enable us to survive.</span>
The light reactions use the reactant water from the equation and release the product oxygen.
Light. That's the chemical equation for photosynthesis
<span>a. chemicals produced by neurons that function as hormones—neurohormones
b. chemicals that act locally on nearby cells—paracrine factors
c. chemicals secreted by presynaptic terminal—neurotransmiters
d. influences same cell type from which it is secreted—autocrine agent
e. chemical secreted into the blood by specialized cells; travels some distance to target tissues—endocrine hormones</span>
