Read the text given below. Form derivatives from the words written in brackets to make them match the contents of the text grammatically and lexically.

Cross the Hymalayas by train
Boasting the latest in engineering technology, the new railway linking Tibet to Central China is the highest railway in the world. The line runs through an environment that is so 1) ... \(friend\) that many of the workers fell critically ill during construction. Inside the carriages, however, an array of electronic sensors secure the 2) ... \(safe\) of the passengers and monitor the air circulation and the levels of oxygen. The trains are also designed to cope with lightning strikes, since the 3) ... \(probable\) of electrical storms is high on the mountain slopes.
However, this new Himalayan railway 4) ... \(develop\) is highly controversial. Although most people agree that it will bring greater 5) ... \(prosper\) to the region, many worry that Tibet’s unique culture will be lost. Moreover, 6) ... \(ecology\) are concerned about the effects on the Himalayan wildlife such as the Tibetan antelope, which is among the most endangered species in the world. The animals are extremely timid and easily disturbed by any human activity.