In single-gene traits, natural selection can lead to which of the following?
a. allele frequency change
b. directional selection
c. disruptive selection
d. founder effect

Answer;

-Allele frequency change

In single-gene traits, natural selection can lead to allele frequency change.

Explanation;

-Allele frequencies can change over time within a single population, and frequently differ between populations. This change is due to four different processes: mutation, selection (natural and artificial), gene flow and genetic drift.

-Random forces lead to genetic drift. Sometimes, there can be random fluctuations in the numbers of alleles in a population. These changes in relative allele frequency, called genetic drift, can either increase or decrease by chance over time.

Option A , I and II only

Explanation:

The study conducted is done only for people or organisations that either started a compost pile or who want to start a compost pile. Thus result III is not at all a valid question for the study conducted.

However, there can be question related to the result of experiments clarifying  the quantity of additives used in the experiment for  example why only 10 Kg of dry water, why not to add more than 1 L of water , why only water is to be added why not some other solvent etc. Thus question I is a valid question.

Also , question II is valid as it asks about expanding the scope of experiment from one type of organic material to all other type of organic matter in the compost.

There fore both question I and II are valid question and thus option A , is correct.