Yeast in bread is considered a uni cellular organism. In the the word it defines the organism, it functions with one cell.

A C4 plant is to be considered an upgrade of a C3 plant. Corn is a perfect example of this. It grows in arid areas and intense sunlight.

A mushroom is an example of a fungus with mycelium. The mycelium within it contributes toward the fact that mushrooms sprout rapidly and multiple areas at once.

Roots of this tree is an example of something containing meristem. This is what promotes the growth of most plants.

This beautiful rose Adam gave me is an example of an adaption of a plant. The thorns protect it from small animals and insects.