Everyday Science

Nitrogen makes up about 78% of the Earth's atmosphere, making it the most abundant element. Oxygen is the second most abundant at about 21%, while hydrogen and nickel are present only in trace amounts or not at all in the atmosphere.

One kilogram is equal to approximately 35.274 ounces. This is based on the exact conversion where one ounce is defined as 28.349523125 grams, so 1 kilogram (1000 grams) divided by 28.349523125 grams per ounce equals about 35.274 ounces. Therefore, option D (35) is the closest and correct answer among the given options.

Night vision devices commonly use infrared waves because these waves are emitted as heat by objects and can be detected even in low light conditions, allowing the apparatus to create a visible image.

Animal wastes are commonly used for biogas generation because they contain organic matter that decomposes anaerobically to produce methane-rich biogas. Forest residues and aquatic plants are less commonly used for this purpose, and 'None of these' is incorrect.

Bt seed refers to genetically modified seeds that produce Bacillus thuringiensis toxin, which is commonly used in cotton to protect against bollworm pests. Therefore, Bt seed is associated with cotton.

Hen and chicken disorder is a physiological disorder that affects tomatoes, causing the fruit to develop unevenly with some parts ripening earlier than others, resembling a 'hen and chicken' appearance.

The tree that sends down roots from its branches to the soil is the Banyan tree. These aerial roots grow downward and help support the large branches, a characteristic feature of Banyan trees.

The troposphere is the lowest layer of the atmosphere, lying closest to the Earth's surface where weather phenomena occur. The other layers are positioned above it in the order: stratosphere, mesosphere, and thermosphere.

Ordinary mobile phones communicate using radio waves, which are a type of electromagnetic wave suitable for wireless communication over distances. Sound waves, infrared waves, and UV waves are not used for mobile phone communication.

Molasses is a thick syrup that is a byproduct of the sugar manufacturing process, obtained after sugar crystals are extracted from sugarcane or sugar beet juice.