_____ helps forests to grow and regenerate.  

Soil helps forests to grow and regenerate.  

Animals help in seed dispersal in different ways. These seeds germinate in the soil to grow into new plamts. The remains of dead animals and plants are decomposed by the microorganisms present in the soil and converted into nutrients. These nutrients get mixed with the soil and are utilized by the plants to grow. Hence, forest is always under regeneration directly or indirectly with the help of soil.