Why is it important to crack - dry
during pond Preparations.

The drying of the pond bottom is the most practical cheap and effective method of eliminating undesirable species in the pond prior to the culture period. Drying oxidizes harmful chemical substances especially sulphides and facilitates mineralization of organic matter. The pond is dried until the soil cracks or when it is firm enough to hold one's weight without sinking more than 5 cm on walking over the surface.

Hope that answers your question.

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.

just finished the test, the answer is d, greg is the least cost-effective because he charges the most for the project