Answer:
A synthetic element is one of 24 chemical elements that do not occur naturally on Earth: they have been created by human manipulation of fundamental particles in a nuclear reactor, a particle accelerator, or the explosion of an atomic bomb; thus, they are called "synthetic", "artificial", or "man-made".
Explanation: hope that helps
C — all others endanger you.
Liquid - takes the shape of the container and maintains volume
Solid- maintain shape
Answer: 2. Decomposition
Explanation:
Synthesis reaction is a type of chemical reaction in which two reactants combine to give a single product.
Decomposition reaction is defined as the reaction where a single substance breaks down into two or more simpler substances.
lithium carbonate → lithium oxide + carbon dioxide

Single replacement reaction is a type of chemical reaction in which more reactive element displaces the less reactive element from its salt solution.
A double replacement reaction is one in which exchange of ions take place.
Let's see
- ∆S refers to the total change in entropy of system.
Graphite was in solid state and oxygen was in gaseous state.
When they synthesized they converted to gaseous state
- So randomness of particles increases
- So entropy also increases
∆S=+ve