Answer:
a) Orangutan prefer to shelter in leafy trees or only leaves
b) One territory is of size 9 sq. km.
Explanation:
a) Orangutans spend a large part of their life in tropical rainforest trees. They prefer to sleep on the bunch of green trees and protect themselves from harmful weather conditions by using broad leaves of rainforest trees. 
b) Each individual territory of a male Orangutan is near about 9 sq. km. and can extend up to 15 square kilometer. In one territory only one male lives along with other females and young ones. 
 
        
             
        
        
        
Answer: alleles
Explanation:
Alleles are different forms of a given gene. Alleles are mutated forms of a given gene which controls a particular trait. For instance, the gene that codes for hemoglobin is denoted with the letter A but the gene has another variant denoted by S. In abnormal hemoglobin S (sickle hemoglobin), glutamate is replaced by valine at position 6 in the amino acid sequence of the two beta chains of hemoglobin. This change in the amino acid sequence causes the red blood cells to have a sickle shape resulting in sickle cell disease. Therefore hemoglobin A and S are alleles of a given gene. 
 
        
             
        
        
        
Answer:
Ionic bond
Explanation:
A bond formed by the electrical attraction between two oppositely charged ions is an Ionic bond.
 
        
             
        
        
        
B.To Understand group behavior through observation
        
             
        
        
        
The answer is programmed cell death