Surface tension is defined as the tendency of elasticity of a liquid surface that makes it to achieve the possible least surface area. It depends upon the intermolecular forces present on the boundary of the surface of the compound and its contact.
n-butane 
is non-polar compound and it consist of only weak dispersion forces that are responsible for any contact with the surface.
In comparison to other given substances, n-butane has the weakest dispersion forces. Thus, n-butane has lowest surface tension.
The sun provides energy through nuclear fusion by fusing the atoms of hydrogen and helium in the suns core, so the answer is D
Answer:
element
Explanation:
we know that helium is a pure substance although helium atoms are sometimes mixed with their isotopes it is still the same element. since there is no other element combined with helium this makes it an element.
