(a) Correct Matches:
Explanation: The rotation of the Earth on its own tilted axis takes approximately 24 hours, defining a single day and creating the cycle of day and night. The Earth’s complete elliptical orbit around the Sun takes about 365.25 days, defining one year and driving the seasons. The Moon takes roughly 27.3 days to orbit the Earth, which governs the cycle of lunar phases and establishes the approximate duration of one month.
(b) (i) Correct Answers:
hydrogen and helium
Explanation: The Sun is a main-sequence star primarily composed of a massive cloud of gas and plasma. Hydrogen constitutes roughly 73% of the Sun’s mass and acts as the primary fuel for nuclear fusion in its core. Helium makes up about 25% of the mass and is the principal byproduct generated when hydrogen nuclei fuse together under extreme heat and pressure.
(b) (ii) Correct Answers:
infrared and ultraviolet
Explanation: Due to its extreme surface temperature, the Sun emits a continuous spectrum of electromagnetic radiation across multiple wavelengths. While its peak emission intensity falls squarely within the visible light spectrum, a massive portion of its radiated energy is also transmitted as infrared radiation (which transfers thermal energy to Earth) and ultraviolet radiation.
