Answer:
Today, one second is defined as “9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom”. That's a mouthful.
 
        
             
        
        
        
Answer:
The wave nature of light is the fundamental resolution of an optimal instrument.
Explanation:
All the optical instruments are working on light that's why they are known as optical instrument. Optics means the behavior of light or sight. Light is an electromagnetic radiation which comes in the category of electromagnetic spectrum. It travels in the form of wavelength. 
So, optical instruments are based on wave nature of light.
 
        
                    
             
        
        
        
I will have to say D) they keep the prey population low so they will be less likely to deplete resources such as food, water, and shelter... hope i helped!! 
        
                    
             
        
        
        
D.Elements continuously cycle between the physical environment and living organisms.
Ecosystem is encompassing all the life on earth in the physical environment that supports it. An ecosystem involves both the biological (plants, animals, human beings) and non-biological (land, water, soil, and atmosphere) community which interacts as a system. More importantly, the living things are very dependent on the abiotic community since it cannot survive by itself. Every animal, plant and human needs the primary physiological needs of water, food and shelter provided by the abiotic system.  <span> </span>