since the water appears clear and no solids can be seen how can the presence of these chemicals in the water be explained

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.

Calculate the frequency of a wave in a spring toy. the wave has a speed of 1.1 meters per second and a wavelength of 0.1 meters. *

The biomedical technique in which a part of the brain is destroyed with electric current is known as a. electroconvulsive therapy b. prefrontal lobotomy c. bilateral cingulotomy d. tardive dyskinesia