Monosaccharides can be grouped as aldehydes and kefone groups, explain their difference and similarities and list four examples both of them

see below

Explanation:  aldoses and ketoses differ in that aldoses have a terminal aldhyde group and ketoses have the -C-CO-C- ketone structure. Aldehydes are more reactive and can be oxidised directly to carboxylic acids. Ketones require the carbon chain to break at the carbonyl group. In cyclic form aldohexoses form a six member ring, ketohexoses a five member ring.

examples of aldoses

Threose CH2OH-CHOH-CHOH-CHO

glyceraldehyde CH2OH-CHOH-CHO

mannose, glucose, altrose, allose etc CH2OH(CHOH)4-CHO

deoxyribose H-(CHOH)3-CH2-CH2OH

ketoses

dihydroxyacetone CHOH-CO-CHOH

ribulose, xylulose CH2OH-(CHOH)2-CO-CH2OH

sedoheptulose CH2OH-(CHOH)-CO-CH2OH

erythrulose CH2OH-CHOH-CO-CHOH

the abdomen (less formally called the belly, stomach, tummy or midriff) constitutes the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. the region occupied by the abdomen is termed the abdominal cavity. the stomach secretes acid and enzymes that digest food. ridges of muscle tissue called rugae line the stomach. the stomach muscles contract periodically, churning food to enhance digestion. the pyloric sphincter is a muscular valve that opens to allow food to pass from the stomach to the small intestine.