Answer: Nitrogen
Explanation:
Harmful algal blooms can occur in lakes, reservoirs, rivers, ponds, bays and coastal waters, and the toxins they produce can be harmful to human health and aquatic life. Harmful algal blooms are mainly the result of a type of algae called cyanobacteria, also known as blue-green algae.
B.https://www.mansfieldct.org/Schools/MMS/staff/hand/genNaturalselection06.htm this is where I got my source.
Climate is long term weather condition in a certain area.
D - Eubacteria and Archaebacteria