Air expands as it warms. Therefore warm air is less dense than cool air. The warm air from the first floor apartments rises to the second floor. People on the second floor require less heating to keep their <span>apartments comfortable.
-Hope this helps </span>

Actually Welcome to the Concept of the Optical Devices.
Now basically here the devices that can spread light over apart are the CONCAVE LENS and Convex mirror.
so the Answer is
C. B and D
Answer: O:right
Explanation: In this case you place your finger on the current, and your fingers should curl showing the way, you must use your right hand in this case, otherwise that would mean the fingers on your left would bend way back, and snap off, (Not really lol, just saying)
Answer:
39.6 m/s
Explanation:
Taking down to be positive:
Given:
v₀ = 0 m/s
a = 9.8 m/s²
Δy = 80 m
Find: v
v² = v₀² + 2aΔy
v² = (0 m/s)² + 2 (9.8 m/s²) (80 m)
v = 39.6 m/s
The chemical symbol for the element zinc is Zn.
<h3>What is element?</h3>
A chemical element is the one which reacts with other elements to form a compound.
Any chemical symbol must have its first letter written in Uppercase. If the element has two letter chemical symbol, then it should be written in lowercase.
Thus, the student wrote Zn as the chemical symbol of Zinc on the whiteboard.
Learn more about element.
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