For giving you understanding ; we need Free O2 but Oxygen is also available in H20 right why dont we use it !!
As the early atmosphere was reducing as there was no free oxygen but it was later produced by chemoautotrophic bacteria !! Living thing release O2 in atmosphere thus making it oxidising in nature and then life evolves !!
The correct answer for both blanks is "Sodium".
Sodium ions are necessary in small quantities for some sorts of flora, but sodium as a nutrient is extra usually wanted in large quantities by using animals, due to their use of it for era of nerve impulses and for upkeep of electrolyte balance and fluid stability. In animals, sodium ions are vital for the aforementioned capabilities and for coronary heart hobby and sure metabolic functions.
The role of deep-sea coral reefs in the environment is to provide critical habitat for many other organisms. So, the correct option is C.
<h3>What do you understand about Coral reefs?</h3>
A coral reef is an underwater ecosystem characterized by reef-building corals.
Coral reefs provide critical habitat for many invertebrates and fishes. These organisms are also known as cold-water corals, as they are found in the deeper and darker part of the ocean where the temperature is extremely low.
Therefore, the role of deep-sea coral reefs in the environment is to provide critical habitat for many other organisms.
To learn more about the Coral reefs, refer to the link:
brainly.com/question/364711
