Read the passage given below and answer the question that follow:

It is claimed that apart from us, only chimpanzees and ants go to war. A student studying the Ridge monkeys, years ago, told me that she had identified seven distinct groups, which had their own territories, the sovereignty of which was sacrosanct. And, yes, occasionally one group might raid the territory of another with the idea of seizing it.

During one evening walk, years ago, I saw this in action - and it was blood-curdling. My path ran through a section of the Ridge, on one side of which the land sloped upwards into what I had dubbed the 'wild section', which had been left to its own devices. On the other side of the path was the landscaped section, with its ornamental plants, park, benches etc. Here, a group of monkeys were feeding quietly.

Suddenly, from the hillside, an avalanche of simians charged down screaming with rage: they swarmed across the path in a torrent and set themselves upon the feeding group, which, shrieking and panicking, fled incontinently in every direction. Caught in the melee, I could only stand still until the chaos had died down.