The correct answer is D. Digestion.
Digestion is termed as the breakdown of food which has large insoluble molecules to small soluble molecules which makes them to be absorbed in the blood plasma.
Based on the way which food is being broken, it will depend on the form of catabolism which is used in the digestion. For example, catabolism is divided into chemical and mechanical digestion where mechanical digestion breaks down large to small pieces of food.
Those pieces of food are accessed by digestive system. In chemical digestion it is the enzymes which broke down molecules of food.
The terrestrial gastropods are the only mollusks that have adapted to all the habitats of the Earth. They dwell in areas of high altitude, mountainous regions, hot and cold places. Land snails live and perform their vital functions on the ground and not in the sea or bodies of fresh water.
Answer: Ribose nucleotides and the nitrogenous bases
Explanation: RNA consists of ribose nucleotides (nitrogenous bases appended to a ribose sugar) attached by phosphodiester bonds, forming strands of varying lengths. The nitrogenous bases in RNA are adenine, guanine, cytosine, and uracil, which replaces thymine in DNA.