State a null hypothesis the marine biologists tested in this investigation.

The natural habitat of COTS is coral reefs of tropical oceans.

Suggest two factors that should be kept constant in the choice chambers so that COTS display normal behaviour.

1

2

A journalist studying Table 1 suggested that either type of light could be used to cause COTS to move away from coral reefs.

Evaluate the journalist's suggestion.

One of the reasons COTS can destroy coral reefs in a short time is because COTS move quickly, allowing them to move from one reef to another.

Table 2 shows the maximum speeds recorded of COTS in constant light.

Calculate the shortest time one COTS would take to move up a coral reef from 66 m under water to 18 m under water in hours of daylight.

Give your answer to the nearest hour.

Answer = ______________ hours