Everyday Science

The tarsal bones are a group of seven bones located in the foot, forming the ankle and part of the foot's structure. Therefore, the correct answer is 'Foot'.

Earth completes one full revolution around the Sun in approximately 365.25 days, which defines the length of a year. This accounts for the extra quarter day that leads to a leap year every four years.

Carbohydrates are primarily composed of sugars and starches. Sugars are simple carbohydrates, while starches are complex carbohydrates, both constituting the carbohydrate group.

Hydrogen has the highest fuel value (energy content per unit mass) compared to charcoal and gasoline, making it the most energy-dense fuel among the options.

Phosphorus is the substance commonly used in match sticks because it ignites easily when struck against a rough surface, enabling the match to light.

Vitamin B12 contains cobalt as a central metal ion in its structure, which is essential for its biological activity. The other options do not contain cobalt.

Green leaves appear green because they reflect green light and absorb other colors. Under red light, there is no green light to reflect, so the leaves absorb the red light and appear very dark or black to the eye.

Biogas is considered a non-conventional source of energy because it is renewable and derived from organic waste, unlike coal which is a conventional fossil fuel. Algae can be a source of biofuel but is less commonly categorized as a direct energy source compared to biogas.

The sun emits a spectrum of light, but the brightest color perceived by the human eye from sunlight is yellow-green, which corresponds to the peak sensitivity of human vision and the sun's emission spectrum.

A gas heater primarily transfers heat to the surrounding air through convection, where warm air rises and circulates, distributing heat effectively. Radiation and conduction are less significant in this context, and environmental pressure is unrelated to heat transfer.