Explanation:

Gas hydrates are ice-like crystalline minerals that form when low molecular weight gas (such as methane, ethane, or carbon dioxide) combines with water and freezes into a solid under low temperature and moderate pressure conditions.

• Most gas hydrates are formed from methane (CH4), which has led to the terms “gas hydrate” and “methane hydrate” often being used interchangeably.
• On Earth, gas hydrates occur naturally in some marine sediments and within and beneath permafrost. They are also speculated to form on other planets.

Hydrate deposits are important for a variety of reasons

• Gas hydrate deposits may contain roughly twice the carbon contained in all reserves of coal, oil, and conventional natural gas combined, making them a potentially valuable energy resource.
• Their decomposition can release large amounts of methane, which is a greenhouse gas that could impact Earth’s climate.
• Sudden release of pressurized methane gas may cause submarine landslides, which in turn can trigger tsunamis.
• Gas hydrates in the ocean can be associated with unusual and possibly unique biological communities that use hydrocarbons or hydrogen sulfide for carbon and energy, via a process known as chemosynthesis.

Hence only statements 1&3 are correct.