A. Oxygen ion
I am not sure but that's the right one I think. If I am wrong then I am sorry
Answer:
Solar Power, HEP (Hydroelectric Power), Wind Power, etc...
Explanation:
These are some common examples of renewable energy source.
Answer:
The specific heat of the alloy 
Explanation:
Mass of an alloy
= 25 gm
Initial temperature
= 100°c = 373 K
Mass of water
= 90 gm
Initial temperature of water
= 25.32 °c = 298.32 K
Final temperature
= 27.18 °c = 300.18 K
From energy balance equation
Heat lost by alloy = Heat gain by water
[
-
] =
(
-
)
25 ×
× ( 373 - 300.18 ) = 90 × 4.2 (300.18 - 298.32)

This is the specific heat of the alloy.
The choices for this problem are bismuth, Bi; platinum, Pt; selenium, Se; calcium, Ca and copper, Cu. I think the correct answer would be selenium. The melting point of bismuth is at a temperature of 544.4 Kelvin. At a temperature of 525 K, it would exist as solid. Platinum melts at 2041.1 K. At 525 K, platinum would be in solid form. Selenium has a melting point at 494 K so that at a temperature of 525 K, it would exist in its liquid state. Calcium has a melting point of 1112 K so it would exist as solid at 525 K. Copper has a melting point at 1358 K, so it would still exist as solid at a temperature of 525 K. Therefore, the answer would only be selenium.