21. The largest contributed factor to the increase of greenhouse gasses is the burning of fossil fuels.

= contributing

22. Ashmont Primary School in London is the first school which decided to outsourcing part of the teaching of mathematics to India via the internet.

= outsource

23. In March 2010, ten energy companies have been given the green light to set up wave and tidal farms off the coast of Scotland in line with the plan to provide energy to 750,000 homes by 2015.

= were given / had been given

24. For primary school children e-learning is a novelty that catches theirs attention for longer periods and engages them in a different way.

= their

25. Most of experts believe that there is a causal link between the economic prosperity of a nation and the health of its people.

= Most

26. An educational pscyhologist shaking public opinion in 1967 by claiming that genetic components had a far more decisive influence on IQ levels than environmental factors.

= shook (type 2 verb)

27. Valium, a drug prescribed as a safe and fast-acting tranquilizer, was found years later to be highly addiction.

= addictive (adjective)

28. Short-wave radiation in the form of visible ultra-violet light from the sun penetrates atmosphere, thereby warming the earth’s surface.

= the atmosphere (article)

29. The government of Uganda has pursuit a comprehensive poverty reduction strategy which addresses the issues of access to appropriate and adequate health care.

= pursued / been pursuing (form of verb)

30. Encountering a sharp decrease in crocodile population, Australia took swift steps to protect and expand existence crocodile habitats.

= existing