What does a capital letter, such as T, represent in Punnet square?

In Punnet square, the capital letters represent the dominant gene and lower case t means recessive gene. so T means Tall and t means Short

Explanation:

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.

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