I would have to say (D.) if it's been 150 years.
Nucleus for what?
Atom? Animal Cell? Plant Cell? Each have different structures.
The coral provides the algae with a protected safe environment (a home) and compounds they need for photosynthesis. The algae in return, produce oxygen and help the coral to remove wastes. Most importantly, zooxanthellae supply the coral with glucose, glycerol, and amino acids, which are the products of photosynthesis.
Answer:
Erosive Forces:
•light particles float
• some particles dissolve into water
• abrasive forces wear down rocks