Detailed Explanation:

Correct Answer: ✅ Option 4 (Statement-I is incorrect, but Statement-II is correct)

Stars live for different lengths of time depending mainly on how fast they consume their nuclear fuel. Although giant stars contain more fuel, they burn it much more rapidly than dwarf stars.

❌ Statement I is Incorrect: Giant stars do not live longer than dwarf stars. Due to their high energy output, they exhaust their fuel quickly and have shorter lifespans.

✅ Statement II is Correct: Giant stars have much higher core temperatures and pressures, leading to a faster rate of nuclear fusion reactions than dwarf stars.

Relationship: Statement II actually explains why Statement I is incorrect. Faster nuclear reactions mean faster fuel consumption, resulting in a shorter lifespan.

Short Notes: Stellar Life Cycle

• The lifespan of a star depends mainly on its mass.

• More massive stars have higher core temperatures and faster fusion rates.

• Giant stars burn fuel much faster and may live only millions of years.

• Small dwarf stars can survive for billions to trillions of years.

• The Sun is a medium-sized star with an expected lifespan of about 10 billion years.

• Red dwarfs are the longest-living stars in the universe.

• Stars generate energy through nuclear fusion, mainly converting hydrogen into helium.

• After exhausting fuel, stars evolve into white dwarfs, neutron stars, or black holes depending on their mass.