Soil acidity (and acidity of anything else, for that matter) is measured on a scale of 1 to 14. Everything below 7 is considered to be acidic. Everything above is considered to be alkaline. Most garden plants thrive at a pH between 6 and 7.5. The reason a pH between 6 and 7.5 is optimal for garden plants is that between 6 and 7.5, phosphorus in the soil is soluble - meaning that it dissolves in water and is taken up by plant roots.
Some of the factors that affect the rate at which particles diffuse include: the particle's molecular weight, temperature, concentration difference, diffusion distance, permeability and surface area. Pressure is also known to affect the rate of diffusion since it increases the speed of molecules.
Best Answer: -- Push and pull factors are those factors which either forcefully push people into migration or attract them. A push factor is forceful, and a factor which relates to the country from which a person migrates. It is generally some problem which results in people wanting to migrate. Different types of push factors can be seen further below. A push factor is a flaw or distress that drives a person away from a certain place. A pull factor is something concerning the country to which a person migrates. It is generally a benefit that attracts people to a certain place.