The least reactive element in the third period is argon.
Answer and Explanation:
Corals are translucid or white, but they look brightly colored because they host symbionts with colorful photosynthetic pigments
. They can host different organisms that live on and among them, giving place to an amazing ecosystem.
One of these organisms is the photosynthetic unicellular microalgae, called zooxanteles, that are colorful and provide nutrients to the coral.
Corals provide shelter and protection to the algae, while algae provide nitrogenated nutrients, sugars, and color to the corals. Algae can store nitrogen in their tissues as nitrogen-rich crystals, which are constantly provided to corals.
This symbiotic relation allows corals to grow in different environments that are poor in nitrogen or other nutrients, such as the tropical clear waters.
When changes in radiation, temperature, or salinity in water occur, corals react to these changes losing these algae and becoming translucid again.
Cell drinking : pinocytosis
cell eating :phagocytsis