Soil erosion is defined as the wearing away of topsoil. Topsoil is the top layer of soil and is the most fertile because it contains the most organic, nutrient-rich materials. Therefore, this is the layer that farmers want to protect for growing their crops and ranchers want to protect for growing grasses for their cattle to graze on.
The peripheral nervous system is made up of two systems; the somatic nervous system controls muscle movement and the autonomic nervous system connects with internal organs.
Answer:
Lichens are not parasitic when they grow on trees, they just use the tree bark as a home. They enrich the soil by trapping water, dust and silt. When lichens die they contribute organic matter to the soil, improving the soil so that other plants can grow there.
Five conditions<span> are required in order for a population to remain at </span>Hardy-Weinberg equilibrium<span>: A large breeding population. Random mating. No change in allelic frequency due to mutation.</span>
Paratism is the practice of living as a parasite in or on another organism. Mutualism is the way two organisms of different species exist in which each individual benefits from the activity of the other.