Everyday Science

Earth is the third planet from the Sun in the Solar System, following Mercury and Venus. This is a well-established fact in astronomy.

The Sun is commonly divided into four main layers: the core, the radiative zone, the convective zone, and the photosphere (sometimes including the chromosphere and corona as additional layers, but the primary classification is four). Therefore, option C (4) is correct.

Dissolved oxygen (DO) in water is typically measured in parts per million (ppm), and healthy water bodies usually have DO levels around 4 to 5 ppm, which supports aquatic life. The other options are either too high or too low to be realistic for DO in natural water.

The Sun contains about 99.86% of the total mass of the solar system, making option D the correct answer. This is a well-established fact in astronomy.

Venus is known as the brightest planet in the night sky due to its thick cloud cover reflecting sunlight, making option B correct. It is neither the smallest, most dense, nor the largest planet.

The Moon takes approximately 27.3 days to complete one orbit around the Earth, known as the sidereal month. This is the time it takes relative to the fixed stars, which is the standard measure for the Moon's orbital period.

One Astronomical Unit (AU) is defined as the average distance between the Earth and the Sun, which is approximately 150 million kilometers. This is a standard value used in astronomy to describe distances within our solar system.

The study of heavenly bodies such as stars, planets, and galaxies is called Astronomy. Astrology is a belief system, Astronautics is the science of space travel, and Astrophysics is a branch of astronomy focusing on the physics of celestial objects.

Rusting of iron is a chemical process where iron reacts with oxygen and moisture to form iron oxide. This involves the loss of electrons by iron atoms, which is oxidation.

Hydrogen peroxide (H2O2) is a reactive oxygen species that can be toxic to living tissues because it can cause oxidative damage. Therefore, it is considered poisonous to tissues. The other options are incorrect as H2O2 does not help line up cell proteins, is not typically used as a catalyst, and does not directly aid in glucose oxidation.