Well since covalent bonds are strong and diamonds contains a lot of covalent bonds, it makes the diamond's melting point and boiling point very high.
The correct answer is:
b: Heluim
Explanation:
The caffeine contains:
carbon , nitrogen , oxygen ,
hydrogen.
Caffeine is a primary nervous system energizer of the methylxanthine class. It is the world's most universally consumed psychoactive drug. Unlike many other psychoactive elements, it is fair and unlimited in nearly all parts of the world. Caffeine can be arranged as an alkaloid, a term used for substances originated as end results of nitrogen metabolism in some plants.
Answer:
appears to be moving back toward unmanned exploration in the form of deep-space satellite exploration.
Explanation:
NASA moved from unmanned probing of space in its initial stage of space exploration to manned space exploration and moon landing and now has gone back to unmanned exploration into deeper space. Deep space is not completely known yet, and the exploration take year and are probably very dangerous for manned exploration for now.