<span>The unknown substance is silver.
I don't see a list of available substances, but let's see if there's something reasonable available that will match. First, let's calculate the density of the unknown substance. Density is mass per volume, so
273 g / 26 mL = 10.5 g/mL
Looking up a list of elements sorted by density, I see the following:
10.07 Actinium
10.22 Molybdenum
10.5 Silver
11.35 Lead
And silver at 10.5 g/ml is a very nice match for the unknown substances' density of 10.5 g/ml.</span>
Explanation:
A light bulb changes electrical energy into <em>heat energy and light energy .</em>
Answer: holding the ball in the air without moving it
Explanation:
When the ball goes up it’s potential energy
Technically speaking, there are many "levels" of a plant for which this may hold true. I think the one you are referring to is the chloroplast. It takes in the light energy from the sun, water and carbon dioxide, and performs photosynthesis on them to produce sugar and oxygen. A leaf would also fit the description as this is a very general question.