K, ca, sc is the right answer. Take a look at table S of your chemistry reference table.
An alloy is the solid solution of a metal or non-metal dissolved in a metal.
B.
The cynobacteria were already there without the oxygen, so that rules out A, and a lot of prokaryotes were anaerobic, so that rules out C. Finally, Photosynthesis does not require oxygen. Instead, Oxygen is a waste product of it. Therefore, it cannot be D. So, we are only left with B
Hoped this helped :D
Answer:
B. He should heat the water to a higher temperature.
Explanation:
Tiny particles that make up water and salt vibrate at higher speeds in hotter temperatures, which mixes the salt and water faster. This causes salt to dissolve much faster.