Why are earth's materials and energy considered to be in equilibrium? (can be multiple answers) earth's materials are recycled and reused constantly earth's materials are all divided in equal amounts energy is balanced and cannot be created or destroyed energy is always converted into usable forms

The correct answer is option A ,  C and D

The earths material is recycled and this can be visualized from the different chain cycles such as nitrogen cycle, carbon cycle , sulphur cycle, water cycle etc. These basic components which constitute all the matter existing on earth are continuously recycled and reused. Likewise the energy obtained from sun is neither created nor destroyed; it is only converted from one form of energy to the other form. Such as heat energy obtained from sun is converted into kinetic energy when it converts water into water vapor.

after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

hope its .