Explanation:
Always behave responsibly in the laboratory. Do not run around or play practical jokes. Always check the safety data of any chemicals you are going to use. Never smell, taste or touch chemicals unless instructed to do so.
Answer:
Atom, smallest unit into which matter can be divided without the release of electrically charged particles.
an element is a pure substance which cannot be broken down by chemical means
Answer: A river delta is a landform created by deposition of sediment that is carried by a river as the flow leaves its mouth and enters slower-moving or stagnant water. This occurs when a river enters an ocean, sea, estuary, lake, reservoir, or (more rarely) another river that cannot carry away the supplied sediment. The size and shape of a delta is controlled by the balance between watershed processes that supply sediment.
I think it is 100 dB .I holp it is help.