What is the difference between an atoll and a high island?

There are a great variety of differences between atolls and high islands, these include how they were formed, the soil quality, population and what they look like.

An atoll is a very small ring shaped reef formed of coral enclosing a lagoon while a high island is larger in area because it is formed from volcanic origin. Also, though atolls have high temperatures of tropical weather throughout the year, their vegetation is poor. This is because their soil is usually coarse, gritty, sandy and low in fertility; the reason being is that it is formed form coral itself. Their trees have shallow root systems whilst high islands are more fertile and have a great variety of plantation. That is why high islands are more populated than atolls.

High islands are bigger than atolls thus means that high islands have mountain peaks and areas for rivers to flow.

Learnt this in Social Studies class.