Consider statements about genetics: 1. Genes are located on chromosomes. 2. DNA replication is semi-conservative. 3. RNA is double-stranded. Which are correct? MCQ with Answer and Explanation

Explanation:
The medulla oblongata is the lowest part of the brainstem, connecting the pons to the spinal cord. It contains vital autonomic centers that control essential, involuntary life-sustaining functions. These include the cardiovascular center (regulating heart rate and blood vessel diameter), the respiratory center (regulating the rate and depth of breathing), and reflex centers for vomiting, coughing, sneezing, and swallowing. Damage to the medulla is often fatal due to the cessation of these vital functions.

Explanation:
Xylem is a complex permanent tissue that conducts water and dissolved minerals from roots to the aerial parts. It consists of tracheids, vessels, xylem parenchyma, and fibers. Phloem transports organic solutes, collenchyma provides flexible support, epidermis protects.

Explanation:
The Rh factor (Rhesus factor) is an inherited protein found on the surface of red blood cells. It was discovered in 1940 by Karl Landsteiner and Alexander Wiener. They immunized rabbits and guinea pigs with the red blood cells of the Rhesus monkey (Macaca mulatta). The serum produced contained antibodies that agglutinated the red blood cells of about 85% of humans. These individuals were designated Rh-positive, and the rest Rh-negative.