<span>The primary psychosocial milestone of childhood is the positive development of self-concept. This usually begins at 18 months, but continues throughout childhood. Self-concept is simply how one views oneself and one's abilities.</span>
In the mid-1800s, an Austrian monk named Gregor Mendel Opens in modal popup window began his own experiments with plants. Unlike his predecessors, he used rigorous scientific methods in his experiments.
Mendel conducted his experiments with pea plants, which he grew in the garden of his monastery. The plants are easy to grow, reproduce quickly, and have several distinct characteristics Opens in modal popup window , or features, that are easy to observe. Characteristics of pea plants include flower color, seed color, and pea pod shape.
<span>Moreover, Mendel knew that each characteristic exists as one of two traits Opens in modal popup window , or forms of the character. For example, the seed color characteristic exists as one of two traits: green or yellow.</span>
Trees, almost all of them are ancient.
