Answer:
D) epithelial tissue
Explanation:
The exchange surfaces of the organisms are the site for an exchange of substances or gases. These surfaces mostly lie within the body and protect the exchange tissues. The exchange surfaces of multicellular organisms are lined with epithelial tissues. These tissues have tightly packed cells with little or no intercellular spaces. The epithelial tissues serve to protect the exchange surfaces. Sometimes, these epithelial linings are modified to perform an additional function. The exchange surfaces are finely branched or folded to have a very large area. The digestive, respiratory, and excretory systems all have such exchange surfaces. 
 
        
             
        
        
        
The six fundmental elements are carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur.
 
        
             
        
        
        
A robin flying south for the winter 
 
        
             
        
        
        
Answer: both weigh the same.
This is a very obvious question just because the lead is heavier that does not mean it ways more than the other. One pound of feathers is the same as one pound of lead
 
        
             
        
        
        
Answer:
Diversity of the community = 2.097
Explanation:
Given:
Number of pitch pines = 134
Number of douglas firs = 24
Number of red pines = 53
Find:
Diversity of the community
Computation:
Simpson's diversity index = N(N-1)/Σn(n-1)
Particular              n	n(n-1)
Pitch pine         134       17822
Douglas firs       24	552
Red pine            53  2756
Total       N=211	21130
So,
D= [211(211-1)] / 21130
D = 2.097
Diversity of the community = 2.097