Answer: Like us, fish also need to take in oxygen and expel carbon dioxide in order to survive. But instead of lungs, they use gills. ... As the fish opens its mouth, water runs over the gills, and blood in the capillaries picks up oxygen that's dissolved in the water.
 
        
             
        
        
        
If a Caterpillar is grown in the dark, then it will be the same color as a Caterpillar when it metamorphisizes
        
             
        
        
        
Answer:
Carrying capacity can be described as the maximum number of population of a species that a particular habitat can hold. 
There are a number of events which effect the carrying capacity like:
Environmental changes like weather conditions might become favorable for a species in a habitat. It might be that a certain weather condition raises more food for a species. Hence, the carrying capacity would increase. 
It might be conditions like drought make the availability of nutrients scarce for a population of species. In this case, the carrying capacity of the ecosystem would decrease.
It might happen that other species might come to live in the particular area. That species will deplete the availability of resources and cause the carrying capacity to decrease. 
If adequate amount of rain fall occurs in an area, it might cause the carrying capacity of a species to increase as there will be more water. But if the water supply becomes scarce, the carrying capacity would decrease. 
 
        
             
        
        
        
The answers A. C. D. are all physical reactions 
The answer is B. Digestion of food 
When food is digested it is chemically broken down 
Hope this help!