Answer:
Dead plant matter
Explanation:
Saprotrophs feed by a process known as absorptive nutrition, in which the nutritional substrate (e.g., dead organism or other nonliving organic matter) is directly digested by a variety of enzymes that are excreted by the saprotroph.
This would mean that it went 5 km for 10 seconds
5 x 10= 50km during that period of time