An enzyme works only with a specific substance like a Fork and knife
Key and lock
On and off switch
A dimmer switch

the main thing i would use is bricks because if there is a hurricane, there is a great possibility for the house to still stand. and i would also use plexiglass windows instead of regular windows because plexiglass isn't prone to breaking.

stimulus is a change in the environment that causes an organism to react. the response is the reaction to the stimulus. some examples of stimuli for zebras are drought, to many predators, and bad feeding grounds such as dead grass or plants. zebras respond to stimuli just like all other living organisms

colors do exist. the color of the sky is actually violet; humans percieve the color of the sky as blue.