These fuels are nonrenewable because they are limited substances which cannot be produced at the same rate at which it is used. Also, they cannot be REused, hence the wording non-REnewable. Hope this answers your question.
It is extremely useful for geologists, because most specimens of a given mineral are very close to the same hardness. ... So, we can conclude that not all the rocks are hard, and the hardness of rocks depends on how the atoms of the rock's minerals are bound to each other and how they are arranged.
23. centromeres
25. mitosis
27. cancer
29. sister chromatid
31. tissues