Answer:
An introduced species, alien species, exotic species, adventive species, immigrant species, ... Non-native species can have various effects on the local ecosystem. ... Some species have been introduced intentionally to combat pests
Explanation:
Lichen will colonize the bare rock.
Trace fossils provide us with indirect evidence of life in the past, such as the footprints, tracks, burrows, borings, and feces left behind by animals, rather than the preserved remains of the body of the actual animal itself.
To answer the question that is: "which factors affect a river's load", we have to understand that all the things mentioned are important. All these options (river's slope, streambed shape and volume of flow) affect the amount of energy that the river has to spend and the way the river spend that energy, so, it is right to mark the alternative d) all of the above.
