Everyday Science

Edward Jenner discovered the smallpox vaccine in 1796, which was the first successful vaccine developed to prevent an infectious disease.

The ozone layer absorbs the majority of the Sun's harmful ultraviolet (UV) radiation, protecting living organisms on Earth from its damaging effects. It does not significantly absorb microwaves, infrared, or X-rays.

Guava is well known for its exceptionally high vitamin C content, which is much higher than many other fruits. Therefore, the correct answer is vitamin C.

The age of a lion can be estimated by observing the color of its nose, which darkens as the lion grows older. This is a commonly used method in wildlife biology to approximate lion age.

Lenses are used to correct vision problems such as long-sightedness (hypermetropia) and short-sightedness (myopia). Convex lenses correct long-sightedness, while concave lenses correct short-sightedness, so both conditions can be corrected using lenses.

Jupiter is the largest planet in the solar system and currently has 79 known moons, making option B correct. The other options list incorrect planets or incorrect numbers of moons.

Sericulture is the cultivation of silkworms to produce silk, making 'silk production' the correct discipline associated with sericulture.

The diameter of the Sun is approximately 109 times that of the Earth, making option D correct. This is a well-established fact in astronomy.

Sunlight is composed of seven distinct colors that can be seen when light is dispersed through a prism, commonly known as the colors of the rainbow: red, orange, yellow, green, blue, indigo, and violet.

A swimming pool appears less deep than it actually is due to refraction, which bends light rays as they pass from water to air, causing the bottom to appear closer to the surface.