The DNA molecule is a double helix, shaped like a twisted ladder.
        
             
        
        
        
Answer:
Photosynthesis is a process in which energy is produced in the plants with the help of sunlight. In photosynthesis, carbondioxide react with water forming oxygen and food material in the form of glucose. It occurs only in plants. 
Respiration is energy releasing process in which energy is released due to the breakdown of glucose molecules with the help of oxygen produces water, carbondioxide and energy in the form of Adenine tri phosphate (ATP). It occurs in all living organisms. 
 
        
             
        
        
        
Answer:
Through photosynthesis, certain organisms convert solar energy (sunlight) into chemical energy, which is then used to build carbohydrate molecules. The energy used to hold these molecules together is released when an organism breaks down food. Cells then use this energy to perform work, such as cellular respiration.
Explanation:
 
        
             
        
        
        
Answer:
C
Explanation:
A. Since
B. Because
C. Although
D. For example
<em>Zebra mussels have been known to have a lifespan of six or seven years in the past but recent discoveries have shown that their average lifespan now ranges between one to two years. Hence, the correct word to fill in the gap would be 'Although'. </em>
<em>The correct option is C</em>