Choose the sentence which has the closest meaning to the original one.

If you have enough time, however, this national park is better explored on foot, with numerous walking trails.

Plastic waste is not biodegradable because it seriously harms marine ecosystems.

Plastic waste seriously harms marine ecosystems since it is not biodegradable.

Plastic waste is not biodegradable, so it seriously harms marine ecosystems.

Plastic waste seriously harms marine ecosystems, but it is biodegradable.

The fishing cats are on the list of endangered species; otherwise, people hunt too many of them.

The fishing cats are on the list of endangered species since people hunt too many of them.

The fishing cats are on the list of endangered species; by contrast, people hunt too many of them.

The fishing cats are on the list of endangered species; therefore, people hunt too many of them.

The forest fire destroyed thousands of trees, so it caused serious air pollution.

The forest fire not only destroyed thousands of trees but also caused serious air pollution.

Although the forest fire destroyed thousands of trees, it caused serious air pollution.

Because the forest fire caused serious air pollution, it destroyed thousands of trees.

Air pollution is increasing rapidly, although many cities are planting more trees.

Many cities are planting more trees, so air pollution is increasing rapidly.

Air pollution is increasing rapidly; therefore, many cities are planting more trees.

Many cities are planting more trees; however, air pollution is increasing rapidly.

Crabs and lobsters increase ocean acidification in the process of building their shells and skeletons.

Ocean acidification increases the number of creatures like crabs and lobsters who need carbonate ions to build their shells and skeletons.

Despite ocean acidification, fewer carbonate ions for creatures like crabs and lobsters to build their shells and skeletons are generated.

Ocean acidification is the reason for fewer carbonate ions available for creatures like crabs and lobsters to build their shells and skeletons.

Oil drilling not only harms marine life but also other factors.

Marine life is not damaged despite the oil drilling.

Oil drilling is the only factor that causes damage to marine life.

Marine life is damaged by several factors, including oil drilling.

It wastes time reading books about plants and animals.

Reading books about plants and animals is favourable.

I'm a big fan of reading books about plants and animals.

Reading books about plants and animals is an activity.