Consider statements about genetics: 1. Genes are made of DNA. 2. Chromosomes are located in the nucleus. 3. RNA is the genetic material in all cells. Which are correct? MCQ with Answer and Explanation

Explanation:
Simple columnar epithelium lines the stomach, intestines, and gallbladder, and functions in secretion and absorption. It often has microvilli (brush border) or goblet cells. Squamous epithelium lines alveoli and blood vessels, cuboidal kidney tubules.

Explanation:
Frederick Griffith in 1928 demonstrated transformation by showing that heat-killed virulent pneumococci could transfer virulence to live non-virulent bacteria. Avery et al. later identified the transforming principle as DNA.

Explanation:
The 'ozone hole' is a severe, seasonal thinning of the stratospheric ozone layer that occurs most prominently over the Antarctic region during the Southern Hemisphere's spring (September to November). This is due to the unique meteorological conditions in the Antarctic stratosphere, including the formation of Polar Stratospheric Clouds (PSCs) during the dark, cold winter, which provide surfaces for chemical reactions that release active chlorine from CFCs, rapidly destroying ozone when sunlight returns.