The substance is called DNA.
Answer:
Eutrophication
Explanation:
When a body water lies in close proximity to any agricultural land, there are high chance of it receiving nutrient from the surrounding land in rainy season. The rich nutrient run off from these land parcels, mixes with the water of existing water body and make it extremely rich in growth nutrients. The excess of nutrients causes uninterrupted growth of algae and lead to algal boom. Oxygen in such water bodies depletes at a fast rate due to the increased productivity thereby harming the water animals living in it.
<span>The aurora borealis (northern lights) form when charged particles emitted from the sun during a solar flare penetrate the earth's magnetic shield and collide with atoms and molecules in our atmosphere. These collisions result in countless little bursts of light, called photons, which make up the aurora.</span>