Comparative

Unfortunately, Robo-fish is ... (expensive) than other ways of measuring pollution

but it will become ... (cheap) in the future.

Reducing the amount of vehicles is a much ... (effective) way to stop pollution.

There's strange new fish in Spanish waters. At 1.5m, it's ... (long) than the average fish.

Water pollution is becoming a ... (serious) problem every year. Scientists used to take water samples to analyze in laboratories.

The effects of global warming on the planet are becoming ... (serious) each year.

This makes it a much ... (effective) way to fight pollution.

It's a lot ... (yellow), too! However, it isn't alive - it's a robot called Robo-fish.

Using solar energy at home is ... (good) for the environment and also makes your heating bill ... (cheap).

But Robo-fish is much ... (quick). It detects pollution and swims to its source.