What do these items have in common?

trees, contouring, terraces

rice farming
architecture
erosion control
paper manufacturing

erosion control

Explanation:

Erosion is caused by a physical agent such as water, air or other. This results in the removal of the top layer of the soil.

Trees, terraces, contouring will control erosion. These will reduce the soil erosion by holding the soil.

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.