Misc: What's the particle reponsible for gravitational forces?

Questions

If sand is melted with limestone and sodium carbonate what is formed?

Agent Blue is a herbicide that was used agaainst the Vietnamese, what type of poisonous compound does it contain?

Which compound forms about 70% of the human body?

What is the force that slows down or stops a moving thing?

The stinking cedar and yellow-wood trees are also known as what?