Answer: True.
Explanation:
Humus are decayed dead plants and animals in the soil. They are decayed organic matter(plants and animals). They are formed by the incorporation of plants and animals matter in the soil by the action of microorganisms. Humus provide nutrients for the soil, increase soil porosity and create good soil tilth. The good soil with help microganisms to perform their actions in the soil and improve soil structure.
Answer: Option B) . a decrease in the amount of oxygen dissolved in
the pond
Explanation:
Anaerobic bacteria are able to survive in the absence of oxygen while aerobic bacteria survive only in the presence of abundant oxygen.
Hence, while reduced levels of dissolved oxygen in the pond decrease the amount of aerobic bacteria like Bacillus; anaerobic bacteria like Actinomyces flourish since they survive on organic substances like methane, cellulose instead.
Answer:
minerals may then be deposited, for example, as stalagmites or stalactites
The water dissolves and carries away the solid rock gradually enlarging the cracks, eventually forming a cave. Ground water carries the dissolved minerals in solution.
Explanation:
Ground water is a strong erosional force, as it works to dissolve away solid rock. Carbonic acid is especially good at dissolving the rock limestone. Working slowly over many years, ground water travels along small cracks.
Answer:
Healthy ecosystems clean our water, purify our air, maintain our soil, regulate the climate, recycle nutrients and provide us with food. They provide raw materials and resources for medicines and other purposes. They are at the foundation of all civilization and sustain our economies.
Explanation:
