Science Review, Update

If you study what is in the last review, you should do well on the exam.

The differences between deciduous trees, cacti, and evergreen trees are:

1. Cacti live in deserts. They have adapted to the long periods without water by storing water AND protecting the water with needles. The needles are really leaves.

2. Evergreen trees are "ever green" which means they are green all year round. They have needles, too, and they never lose all their needles at once.

3. Deciduous trees are found in deciduous forests. They lose their leaves in the fall and grow new leaves in the spring.

Also, what you need to know about oxygen and carbon dioxide is that they are both part of photosynthesis. Plants need carbon dioxide to create food during photosynthesis, and then they release water, which has oxygen in it. People and animals need oxygen, but we breathe out carbon dioxide. Plants need carbon dioxide and create oxygen. So we need each other.