Desertification extends beyond the expansion of existing deserts to include land degradation due to human activity in drylands. Land degradation destroys or reduces the productivity of the soil, and is caused by excessive and unsustainable activities such as deforestation, overgrazing, poor land management, soil salinization, and soil erosion.
Sure hope this helps you :D
Answer;
-Green plants are responsible for oxygen in the atmosphere.
Explanation;
-Green plants undertake a process of photosynthesis, in which they use energy from the sun, carbon dioxide and water to form simple sugars and also release oxygen to the atmosphere. The simple sugars from the process may be used by the cells for energy or be stored in form of energy for future use.
-Oxygen is a product of photosynthesis which is released to the atmosphere.
The answer is B
C pairs with G, T pairs with A but in RNA T is replaced with U so A pairs with U