Humans, when exhaling release carbon which helps them to make sugar, and as a biproduct plants release oxegen which humans inhale.
        
             
        
        
        
The first one is commensalism. The second one is mutualism. The last one is parasitism.
        
             
        
        
        
Answer: The structure and curvature of the Earth results in beams of sunlight glancing off the equator and reaching other areas of the Earth. This means that the areas at the equator receive more energy as the sun's rays hit them directly. :)
 
        
             
        
        
        
<h2>Gelatin </h2>
Explanation:
Gelatin is a differential medium which tests the ability of an organism to produce an exoenzyme, called gelatinase (this enzyme hydrolyzes gelatin)
When gelatin is at a temperature below 32°C (or within a few degrees thereof), it is a semisolid material and at temperatures above 32°C, it is a viscous liquid
When gelatin is broken down, it can no longer solidify and if an organism can break down gelatin, the areas where the organism has grown will remain liquid even if the gelatin is refrigerated
No the conclusion by student is not right because the tube must be runny after incubation followed by refrigeration to be considered gelatinase positive
 
        
        
        
After passing through the cornea, light travels through the pupil (the black dot in the middle of the eye). The iris—the circular<span>, colored area of the eye that surrounds the pupil—controls the amount of light that enters the eye.</span>