When it comes to something like food preferences, how do genetics and the
environment influence traits?
• How are traits generally passed from parents to offspring?
• How can dominant-recessive relationships influence which trait is expressed in the
phenotype of the organism?
• How is the expression of genes influenced by other genes and the environment?

1. Genetics and environment influence the trait as it depends upon the adaptation made according to availability and environment.

2. Traits are passed onto either parents after fertilization when 2 genes from either parent is received.

3. Dominant trait is responsible for the phenotype of the individual.

4. The expression of gene is seen by the phenotype expressed depending upon the environmental factors.

Explanation:

The food preferences are based on the traits adapted over the time for digestion and method of eating due to natural selection. The occurrence of beneficial trait for digestion become common in the population as these traits are transferred for better survival and evolution.

The traits in an organism is passed on from parents. During fertilization one allele from each parent is passed onto the progeny. 2 alleles together are called gene. In the process of meiosis only one chromosome is present in germ cell hence no homologous chromosome thus only one allele for the trait is present in each parent.

The alleles of dominant trait mask the effect of recessive alleles during phenotype expression. According to law of complete Dominance the dominant trait gets expressed and recessive trait do not get expressed.

The temperature, external environment, chemicals, light factor, diet etc influences the expression of genes in certain organisms. The effect of these can be seen on the phenotype of the organism.  

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."