I would say none because thats the only one that makes any sence.
Sun spots- dark circles on the sun’s surface that I believe are areas of cooler temperatures.
Solar flares- arcs of fire that leap from the sun’s surface. Nothing special, they’re a daily roumaine for the sun
B. 1, 2, 1, 2. You balance the equation by making sure there are equal elements on both sides.
I’m not sure if there was important information in the question before this one, but the answer based on the info I have is B.
The density of water is 1kg/L. Since the density of the block is less, it will float.