The photosynthetic dinoflagellates called zooxanthellae have a relationship with the corals in which they live.

mutualistic
parasitic
predatory
commensal

The photosynthetic dinoflagellates called zooxanthellae have a MUTUALISTIC relationship with the corals in which they live.

Explanation:

The relationship that exist between dinoflagellates and corals is simply a symbiotic or mutualistic relationship which entails both organisms benefits from each other.

1. (1.2kw)x(15/60hours) = .3kwh --> a

2. (5kw)x(90/60hours)x(8cents/kwh) = $0.60 --> d

3. microwave --> 1200 watts = (1.2kw)x(6/60hours) = .12kwh

coffee-maker --> 900 watts = (.9kw)x(10/60hours) = .15kwh

therefore, it requires more energy for the coffee-maker to do the same amount of work.

so the answer is a.

heat a spark and oxygen