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.
XFormaldehyde is a most simple but highly reactive organic compound. XIt is a natural trace compound and an important substance for chemical. and technical applications and for hygienic purposes. XIt is used for the formulation of wood-based panel adhesives. XIt is a very valuable compound in these applications and difficult to. substitute.