Answer:
1. The standard metric unit of length is a meter.
2. A proposed explanation for a scientific problem is a hypothesis.
3. The standard unit of volume is a liter.
4. The curved top surface of a liquid column is the meniscus.
5. A quantity in an experiment that remains unchanges or constant is a controlled variable (control)
6. The amount of matter in an object is mass.
Answer: Sodium also floats on the surface, but enough heat is given off to melt the sodium (sodium has a lower melting point than lithium and the reaction produces heat faster) and it melts almost at once to form a small silvery ball that dashes around the surface.
Explanation:
4 x 1000 so 4 kilometers are equal to 4000 meters