By people sailing or drifting from southeast Asia
The correct options are:
- Improved engines; engines were improved significantly so that they can have the same power and agility but by using less fuel.
- Cleaner burning fuels; it has been invested a lot of time and money into improving the fuels and making them as effective as possible but also removing or lowering the most dangerous components towards the environment.
- Catalytic converters; this devices for exhaust emission control manage to convert the toxic gasses and polutants into less toxic pollutants by managing to catalyze a redox reaction.
The correct option is LOESS.
Loess refers to a compacted yellowish deposit of wind blown sediments which is usually found extensively in the mid latitudes. Loess is formed by the accumulation of dust that had been blown by the wind. Scientists believed that about 10% of the earth's land area is covered by loess.<span />
