Why blood is classified as tissue in cellular organization?

Blood is considered as a connective tissue .

Connective tissues have cells scattered throughout an extracellular matrix. They connect different body systems. Blood is considered as a type of connective tissue because of two reasons.

(i) Like the other connective tissues, blood is mesodermal in origin.

(ii) It connects the body systems, transports oxygen and nutrients to all the parts of the body, and removes the waste products. Blood has an extra-cellular matrix called plasma, with red blood cells, white blood cells, and platelets floating in it.

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.