Mil
you want to test the effect of soil acidity on plant growth. which of the
following is an example of a controlled experiment to test this?
o
a. the plant type, soil acidity, amount of light, and amount of water
are all varied and studied in a laboratory,
o
b. soil acidity and height of plants growing in a 10 m2 yard are
measured twice in july and twice in august,
c. the soil acidity of plants in a garden that get light and water from
their surroundings is increased after the plants grow to a height of
100 cm.
o
d. the plant type, amount of light, and amount of water are kept
constant while soil acidity is varied for plants in a greenhouse.

vanderwaal's forces of attraction are the electrostatic intermolecular forces that exist in a molecule due to the temporary or permanent dipoles that are developed in a molecule. in , the major intermolecular forces are dipole-dipole interactions as the molecule is polar (bent structure). so the vanderwaal's forces of interaction in between molecules are the permanent dipole-dipole interactions that develop due to the dipole that exists in between the polar h - s bond. the positively charged hydrogen atom is attracted towards the negative end of the dipole that is sulfur of the adjacent molecule. therefore, these forces of attraction are relatively stronger than that of london dispersion forces that exist in non polar molecules.