Answer:
B) Absence of native grasses
Explanation:
The grasses, which acted as a windbreak and whose roots anchored the soil in place, were overgrazed and/or removed to allow for farming. Once a few years of severe drought affected the area, any wind storm was able to blow the topsoil away, rendering the farm land of the Great Plains virtually unusable in many areas. Ground cover is an essential part of sustainable agriculture.
1. Biological control is the intentional manipulation of natural enemies by humans for the purpose of controlling pests.
2. Mechanical control includes mowing, hoeing, cultivation, and hand pulling.
3. Chemical control is the use of herbicides.
Answer:
Using the concept of relative dating
Explanation:
Scientists use the concept of relative dating principles to determine when the Great Oxidation event occurred.
Relative dating is the process of placing ancient event in their proper time sequence based on the relationship between rock lithologies.
- An event like the great oxidation will have significant chemical, biological and physical effect on the rock units.
- Rocks that form during this period in time will have very unique chemical signatures.
- Therefore, by studying these rocks, the age of the layer can be fixed when we compare it to the standard geological column.
Secondary consumer is the answer.
Answer:
Nitrate deficiency
Explanation:
Plants absorb nitrates in water through their roots. Nitrates are present in high levels in plant fertilisers. Without nitrates, the amount of chlorophyll in leaves reduces. This reduces the plant's ability to photosynthesise and grow properly, which reduces the farmers' crop yield .
