There are 25 million to a billion different T-cells in your body. Each cell has a unique T-cell receptor that can fit with only one kind of antigen, like a lock that can fit with only one shape of key. Antigens and receptors work a lot like a lock and key. Each of the 25 million to a billion different T-cells fit with a different shape of antigen.
Motivating operation. Motivating operation (MO) is a behavioristic concept introduced by Jack Michael in 1982. It is used to explain variations in the effects in the consequences of behavior. Most importantly, a MO affects how strongly the person is reinforced or punished by the consequences of their behavior.
APOSTROPHE-a figure of speech in which a person not present is addressed. ASSONANCE-is a close repetition of similar vowel sounds, usually in stressed syllables. ATMOSPHERE / MOOD-is the prevailing feeling that is created in a story or poem. CACOPHONY-Harsh sounds introduced for poetic effect-sometimes words that are difficult to pronounce. CLICHE-an overused expression that has lost its intended force or novelty.