Answer:
B) Nitrogen-fixing bacteria and lightning
Explanation:
Nitrogen cycle is the natural process in which atmospheric nitrogen is converted into nitrite and nitrate with the help of bacteria.
Nitrogen cycle is directly dependent on nitrogen-fixing bacteria and lightning.
As bacteria are responsible for most of the chemical conversion in the nitrogen cycle such as nitrogen fixation (first step) is done by soil bacteria (Cyanobacteria) that form ammonia, which is toxic to plants; nitrification in which ammonia is converted into nitrites and nitrates with the help of Nitrobacter and denitrification bacteria involve Pseudomonas, and Achromobacter which convert nitrite and nitrate into nitrogen.
The lightning breaks nitrogen molecules and allow it to combine with oxygen in atmosphere which further dissolve in rain and form nitrates.
Hence, the nitrogen cycle is most directly dependent upon nitrogen-fixing bacteria and lightning and the correct option is B.
It creates a vacuum that causes the lungs to fill the open cavity and then when it is closed off it returns to its normal shape
Evolutionary theory, atomic theory, gravity, quantum theory and plate tectonics.
Answer:
eutrophication
Explanation:
Eutrophication refers to a situation in which the aquatic environment becomes excessively enriched with nutrients. This leads to algal blooms in aquatic habitats such as lakes. These nutrients come from Fertilisers used in farming, which find their way into water bodies through run-off thereby increasing nutrient levels.
Excess nutrients causes phytoplankton to grow and reproduce at an alarming rate resulting in algal blooms. This bloom disrupts the balance in the ecosystem leading to many problems.
The algae may end up using all the oxygen in the water, causing oxygen shortage for aquatic life. Some of the algae may die, their decay may lead to further oxygen depletion. As oxygen is depleted, aquatic organisms may also begin to die.
