Answer:
B. a nuclear reactor core (1000°C)......
Good laboratory technique demands clean glassware because the most carefully executed piece of work may give an erroneous result if dirty glassware is used. In all instances, glassware must be physically and chemically clean and in many cases, it must be bacteriologic-ally clean or sterile.
384000000m
to change from m to km you just need to divide that give unit in Meters by 1000
which equals,
384000
so,
384000000 meters = 384000 kilometers