Questions

In soil, organic matter consists of plant and animal material that is in the process of decomposing. When it has fully decomposed it is called humus. Soil organic matter serves as a reservoir of nutrients for crops, provides soil aggregation, increases nutrient exchange, retains moisture, reduces compaction,... 

This humus is important for soil structure because it holds individual mineral particles together in clusters.

The given sentence is grammatically correct and there is no error.

India has said it aims to reduce the emissions intensity of its GDP by 33-35% by 2030 from 2005 levels and achieve 40% of its cumulative electric power of around 350GW installed capacity from non-fossil fuelbased energy resources, mainly renewable power. The statement comes ahead of the UN Framework Convention on Climate Change (UNFCCC) to be held in Paris in December 2015, where countries would try to forge a new global climate agreement based on “climate justice" and principles of equity and common but differentiated responsibilities and respective capabilities.