g A parasite of the California Killifish, the trematode Euhaplorchis californiensis, encysts in the fish's brain, can causes it to swim up to the surface of the water and flash it's bright silver belly upwards. It's likely because:

explanation:

on disadvantage of hydroelectric power is the cost. another disadvantage of using hydroelectric power is finding a water source powerful enough to harvest hydroelectric power.

energy per photon is e = h*c / λ  

e = 6.63*10^-34 * 3*10^8 / 6*10^-7 j = 3.315*10^-19 j  

nr. of photons = 10j / 3.315*10 = ^-19 j per photon = 3.02*10^19 photons