Answer:
The correct answer is hydrogen.
Explanation:
Stars in the main sequence will remain in the main sequence as long as their cores contain hydrogen atoms. This is because main sequence stars run on the hydrogen atoms within their core to prevent them from falling to the force of gravity. Once these hydrogen atoms run out, the star is no longer considered a main sequence star, gravity takes hold, and the star collapses.
Answer: The most abundant gas in the atmosphere is nitrogen.
Explanation:
The Earth’s atmosphere is composed of approximately 78 percent nitrogen, 21 percent oxygen, 1 percent argon and trace amounts of other gases that include carbon dioxide and neon.
The correct answer is option 1. It should be noted that a catalyst does not lower or decrease the activation energy because instead it provides an alternative route for the reaction to proceed. This speeds up a chemical reaction without being changed.