Explain how human activities can intensify, or even cause a landslide.

Several factors that contribute to landslide are:
- Gravity
- The slope/angle of the land
- The density/composition strength of the land

Human activities such as road constructions, could influence the angle/slope of the land that increase the intensity of the landslide.
Since Trees and other plants anchor soil in place and prevent rain and floodwaters from eroding too much. other activities such as deforestation, land mining, fracking, etc could destroy the composition and the strength of the land which make it unable to sustain all of its particles, that could cause a landslide.

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