In cladogram what occurs at a node

Cladograms are tree-like diagrams used to show relationships between different organisms. The node represents the end of the ancestral taxon under consideration, the stems and the species that split from the ancestor.

The answer to this will be from your lab notes/procedure. it would be best to ask another student who participated in the lab as we do not know what was done, what enzyme or if the temperature is celsius or fahrenheit. if i were to guess though i'd say the rate stopped due to enzyme denturing at high temperature