Choose all that apply : growth *occurs only in multicellular organisms **only increases size of cells ***usually increases the complexity of an organism's structure is unpredictable

 usually increases the complexity of an organism's structure

is unpredictable

Explanation:

Growth is define as the considerable increase in the size, age, height, length and  weight of the organism. With the increase in the growth of the organism the complexity in structure of the organism also increases due to increase in the number and size of the cells. The growth is unpredicatable phenomena due to factors such as availability of food and water, genetic and environmental factors.

that is wrong, its not thymus.