It is a scientific hypothesis. A scientific hypothesis must be testable, however there is a significantly more grounded necessity that a testable speculation must meet before it can truly be viewed as logical. This foundation comes essentially from crafted by the rationalist of science Karl Popper, and is called "falsifiability".
<span>The answer is the first option. Enzyme and substrate bind using a lock-and-key mechanism. Enzymes act on a specific substrate and a substrate needs a specific enzyme, this is what is called a lock-and-key mechanism. Enzymes and substtates are like a key and a lock, one is for each other.</span>
Energy from the sun that is neither reflected nor absorbed by the atmosphere passes through the atmosphere to the surface. The ozone layer absorbes most of the ultraviolet radiation, water vapor, and carbon dioxide absorbs infared radiation, clouds, dust, and other gases also absorb energy.