How does Peter Dickinson use imagery in Eva?

Examples of Imagery:

"She felt a sudden surge of happiness, of contentment to have awakened on such a perfect morning. It was like being born again. A morning like the first morning of the world."

"...the clamor and the jostling, people, people, people. They were the air you breathed, the sea you swam in. But if you weren't people, you stifled, you drowned - this feeling of pressure, of loneliness and strangeness in the crowd, was different from the sort of depression and sadness Eva still sometimes woke with ... this was something else ... not what the human part of her felt about being chimp, but what the chimp felt about being human."