Answer: According to Darwin theory of evolution the struggle for existence is considered as major part for competition among living things. 
Explanation:
Coexisting species that belong to the same genera compete for same kind of resources for their survival. Some phenotypic variations gives an survival advantage over others. The superior ones dominate the inferior ones and compete for resources. The one who receives the resources like mates, food, shelter, and others the chances of survival also increases considerably. 
 
        
             
        
        
        
Sun provides energy to plants, which use it to make food from soil nutrients, which is eaten by animal, which is eaten by another animal, that produces waste and die, that decomposes and adds nutrients to the soil, which plants use with sunlight to make food from soil
        
             
        
        
        
Answer:
Size of particle.
Explanation:
Size of the particles that are diffusing is the factors that greatly affect the rate of diffusion. The rate of diffusion decreases if the thickness of the membrane becomes doubled while on the other hand, if the surface area of the membrane increases it doubled the rate of diffusion of the cell. If the size of particles is very small so it will diffuse if the membrane has double thickness.
 
        
             
        
        
        
Answer:
Answer: 2
Explanation:
I do not not know a VOC resource is, but it is not the answer. The answer is B, a rapidly renewable resource. 
Somethings are by products. Silver and Gold can be byproducts of copper, but Bamboo is a primary resource. You use it as soon as you grow it.
Answer 2