Downward pull of gravity can cause materials to move from areas of high elevation to areas of low elevation. The force of gravity can cause rocks and glaciers to move down mountain slopes, and also cause rivers to flow toward the oceans. Landslides are the sudden mass erosion of rocks down a hill.
I believe the answer is c. because of Darwin's theory of evolution..
Explanation:
kingdom - plantae
Divison - Magnoliophyta
Class - Liliopsida
Order - Poales
Family - poaceae
Genus - Chusquea
Species - C. antioquensis
They have fibrious root system.
It's empty or fairly large, making the sounds from your hands bounce of the walls and therefore having it echo
