A student makes several measurements of the density of an unknown mineral sample. She then reports the average value of these measurements. The number of significant figures she uses in her result should be a measure of its A) accuracy.
B precision
C) systematic error.
D) determinate error.
E) human error.

B). Precision.

Explanation:

During the course of measurements, two important factors are been seen to play key part which are accuracy and also precision. Precision here can reflect to the closeness of an answer towards the main value even though accuracy can show that too. Also it can show series of values been reproduced in the measurement flow; though in some cases can be a bit far from the actual value. Also its values are swen to be different because of repeatition and alsio in some cases, observational errors too.

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.