At the core of biology and other sciences lies a problem-solving approach called the scientific method. 1  Make an observation. 2  Ask a question. 3  Form a hypothesis, or testable explanation. 4  Make a prediction based on the hypothesis.  Test the prediction.
Xi. Xi is the 14th letter of the Greek alphabet. It is pronounced in Modern Greek, and generally or in English. In the system of Greek numerals, it has a value of 60. Xi was derived from the Phoenician letter samekh. Xi is not to be confused with the letter chi, which gave its form to the Latin letter X.
The noun XII has 1 sense: 1. the cardinal number that is the sum of eleven and one. Familiarity information: XII used as a noun is very rare. â¢ XII (adjective). The adjective XII has 1 sense: 1. denoting a quantity consisting of 12 items or units. Familiarity information: XII used as an adjective is very rare.he noun XII has 1 sense: 1. the cardinal number that is the sum of eleven and one. Familiarity information: XII used as a noun is very rare. â¢ XII (adjective). The adjective XII has 1 sense: 1. denoting a quantity consisting of 12 items or units. Familiarity information: XII used as an adjective is very rare.