Research  ....................... that the global demand for energy is expected to triple by 2050. 

• benefits

• indicates

• values

• stores

One  ......................... of solar power is that it is renewable. 

• device

• store

• benefit

• innovation

The wheel is one of the most ................. inventions of all time. Without it, we could have to walk long distances. 

• valuable

• beneficial

• inventive

• expensive

Bottles are useful  .......................... for water and other liquids.

• containers

• benefits

• devices

• innovations

Before refrigerators were invented, people could not easily ....................... fresh meat.

• store

• contain

• invent

• indicate

Blood tests and X-rays can help doctors .......................... diseases.

• invent

• indicate

• identify

• innovate

Scientists can study the day-to-day movements of an animal by using a tracking ..................... .

• prevention

• device

• container

• design

There have already been several technological ....................... this century, such as electric cars. 

• equipments

• benefits

• stores

• innovations

For many people, an important .................... of regular exercise is that it improves their mood.

• innovation

• value

• benefit

• device

The library does not have room to ..................... extra books, so it is having a book sale.

• invent

• store

• indicate

• design