The table below shows the number of nucleotide differences between a region of mitochondrial DNA in humans, chimpanzees and a Neanderthal - VCE - SSCE Biology - Question 6 - 2003 - Paper 1

The presence of 77 nucleotide differences does not necessarily equate to 77 distinct base substitutions. Some mutations can be reversible, which means a change could revert back to the original state. Consequently, the 77 differences represent the minimum number of base substitutions that have occurred, as other substitutions might have balanced out or reverted.

Skeletal structure or morphology may be used to help determine the evolutionary relationship of Neanderthals with humans and chimpanzees. Comparative anatomy can provide insights into the evolutionary lineage and traits shared among these species.

Carbon dating can be used to estimate the absolute age of the Neanderthal fossil, as the fossil is approximately 25,000 years old.

To determine the relative age of the fossil, stratigraphy can be used. This method involves examining the layers of rock in which the fossil was found, with the understanding that older layers are at the bottom and younger layers are at the top.