The element that is a component of the oxygen-carrying protein in blood is: MCQ with Answer and Explanation

Explanation:
Tissue culture is a technique where plant cells, tissues, or organs are grown on a synthetic nutrient medium (like MS medium) under aseptic conditions to regenerate whole plants. It exploits totipotency. It is used for micropropagation, production of disease-free plants, and conservation. Cloning produces genetically identical individuals, genetic engineering alters DNA, hybridization crosses different varieties.

Explanation:
Porifera (sponges) are characterized by the presence of a complex water canal system (canal system) used for food gathering, respiratory exchange, and waste removal. Water enters through numerous small pores called ostia and exits through a large opening called the osculum. They are mostly marine and asymmetrical.

Explanation:
Salivary glands secrete saliva containing salivary amylase (ptyalin) which begins starch digestion. The stomach's gastric glands secrete HCl, creating an acidic medium for pepsin action. Bile is synthesized continuously by the liver, stored, and concentrated in the gall bladder, but not produced by it. Therefore, statements 1 and 2 are correct, while 3 is false.