Why must controls (such as plants given water only) be used in the fertilizer experiment described in the study guide?

The process by which natural forces move weathered rock and soil brim one place to another is called

Twin boys have girlfriends one of the couples have a baby would the dna of the lil baby be the same as the couples dna bc the boys are identical twins

Four different thermometers were used to measure the temperature of a sample of pure boiling water. the measurements are recorded in the table below. thermometer temperature reading 1 temperature reading 2 temperature reading 3 w 100.1°c 99.9°c 96.9°c x 100.4°c 102.3°c 101.4°c y 90.0°c 95.2°c 98.6°c z 90.8°c 90.6°c 90.7°c the actual boiling point of pure water is 100.0°c. what can be concluded from the data about the reliability and validity of the thermometers?