Consider the following statements regarding photosynthesis: 1. Light reactions occur in the thylakoid membranes. 2. Oxygen is released from carbon dioxide. 3. ATP and NADPH are produced in the light reactions. Which of the above is/are correct? MCQ with Answer and Explanation

Explanation:
The esophagus is a muscular tube (about 25 cm) that propels swallowed food from the pharynx to the stomach via peristalsis. The trachea is the windpipe (air), larynx is the voice box, bronchus is a lung airway. The esophageal sphincters prevent reflux.

Explanation:
Rheumatoid arthritis is an autoimmune disease where the immune system attacks the synovial membranes of joints, causing inflammation and joint damage. Tetanus is bacterial (Clostridium tetani), typhoid is bacterial (Salmonella typhi), malaria is protozoan (Plasmodium). Autoimmune diseases result from failure of self-recognition by immune cells. Other examples: type 1 diabetes, multiple sclerosis, lupus.

Explanation:
ELISA (enzyme-linked immunosorbent assay) uses enzyme-linked antibodies to detect and quantify specific antigens or antibodies in a sample. PCR amplifies DNA, Northern blotting detects RNA, Southern blotting DNA.