Question

4 one trigger of mass movements is the pores in sediments filling with ______

Explanation:

Mass movements (like landslides) can be triggered when sediment pores fill with water (moisture). Water adds weight and reduces friction between sediment particles. Debris, plants, or soil alone don't trigger it this way; water's role in pore - filling is key for mass movement initiation.

Answer:

Assuming the options are (from the visible context, likely related to mass movement triggers): The option related to water (e.g., if one of the options is "water" or "moisture", that would be the answer. Since the text is a bit unclear, but based on geological knowledge, the trigger is pores in sediments filling with water (or similar liquid - based option among the choices). If we assume the options are like: (let's say the third option is "water" - but due to image clarity, the correct option is the one representing water/moisture as the pore - filling substance for mass movement trigger).

(Note: Since the original image's text is blurry, but based on the topic of mass movements in geology (Natural Science - Geography/Geology subfield), the correct answer is the option that is "water" or the equivalent term in the choices. If we take the standard geological knowledge, the trigger is pores in sediments filling with water, so the answer is the option corresponding to water (e.g., if the third option is "water", then the answer is that option.))