Well, it is possible that those stop codons have dual functions. They can act as stop signals or, on the other hand, they can be used to incorporate amino acids.
Other explanation is that multiple stop codons may reduce the rate of nonsense mutation.
The answer is C, that is the correct answer
Could be to do with the basic needs of plants: C02, particular nutrients (nitrogen, phosphorus, potassium) and especially sunlight. Most plants aren’t adapted like coral with algae that provides them with oxygen and the lack of need for sunlight.
