What conditions must occur before nuclear fusion begins during star formation?

What is bromine+calcium iodide--> calcium bromide +iodine balanced

An uncovered pot of water lies out in the sun. which statements correctly describe what happens at the surface of the liquid water? 1. the vapor pressure remains constant regardless of the water temperature. 2. the vapor pressure is produced by water molecules that have evaporated. 3. the vapor pressure increases as the sun heats the water in the pot. 4. evaporation stops once the vapor pressure reaches a certain point. 5. evaporation and condensation both occur on the liquid’s surface.

Which of these questions is scientific? what is the age of earth? should oil drilling be banned? should medicines be tested on animals? what is the most interesting subject to study?