Which of the following is NOT a nitrogenous base found in DNA? MCQ with Answer and Explanation

Explanation:
Antonie van Leeuwenhoek, a Dutch tradesman, is credited as the 'father of microbiology'. In the 1670s, using his own handcrafted, high-quality single-lens microscopes (which could magnify up to 270x), he was the first person to observe and describe living, single-celled organisms, which he called 'animalcules'. These included bacteria, protozoa, and spermatozoa. Robert Hooke observed dead cells (cork) and coined the term 'cell'.

Explanation:
Amylase (ptyalin in saliva, pancreatic amylase in intestine) hydrolyzes starch (a polysaccharide) into maltose (a disaccharide) and dextrins. Lactase breaks lactose, lipase digests lipids, protease digests proteins. Salivary amylase works at neutral pH, pancreatic amylase in the small intestine. Maltase then breaks maltose into two glucose molecules.

Explanation:
The most unique and defining characteristic of Class Aves (birds) is the presence of feathers, which are modified scales used for flight and insulation. Birds are warm-blooded (homeothermic), have a four-chambered heart, and possess a beak instead of jaws. Mammary glands and external pinnae are features of mammals.