Which scientific investigation does not include dependent and independent variable?
1.observing and counting bird populations
2.studying the effect of temperature on bacterial reproduction rates
3.investigating the effect of mass on the speed at which an object falls
4.testing a model car's air flow resistance at different wind speeds in a wind tunnel

Linda and julia are trying to determine whether their ideas are scientific or pseudoscientific. linda's idea is free of bias. julia's idea gives the same result when tested repeatedly. which statement is correct about linda and julia's idea?

The same agricultural practices are used in every country of the world. select the best answer from the choices provided t f

Membrane vesicles containing an internal sodium chloride (nacl) concentration of 0.14 m are placed into separate beakers each containing a different solution. the first beaker contains 0.14 m sucrose, while the second beaker contains 0.14 m calcium chloride (cacl2). the temperature is 25°c. what is the solute potential inside the vesicles, expressed in units of mpa?