Which of the following is a nitrogen-fixing bacterium in legume roots? MCQ with Answer and Explanation

Explanation:
In eukaryotes, complete oxidation of one glucose molecule via glycolysis, Krebs cycle, and electron transport chain yields a net of about 36-38 ATP molecules (depending on shuttle systems). Glycolysis yields 2 ATP, Krebs 2 ATP, and oxidative phosphorylation 32-34 ATP. This is much higher than anaerobic respiration (2 ATP).

Explanation:
Pericardium is outer sac, endocardium inner lining. Myocardium is the middle muscular layer; the outermost is epicardium (visceral pericardium). So 3 is incorrect.

Explanation:
The Haversian system (osteon) is the characteristic structural unit of compact (cortical) bone in mammals. It consists of a central Haversian canal (containing blood vessels and nerves) surrounded by concentric layers of calcified matrix called lamellae. Between the lamellae are small spaces called lacunae, which house osteocytes (bone cells). Canaliculi connect the lacunae. Bird bones are pneumatic (hollow), and cartilage lacks Haversian systems.