How many gene pairs are needed to affect skin color?

 At least four pairs of alleles are involved in skin color, and there are nine (or more) shades of skin color. The bionomial expansion (a + b)6 can also be used to display the cross in Table 1, where the letter a represents the number of capital letters and the letter b represents the number of small case letters.

Explanation:

1. loamy sand is about 80% sand with 10% clay and defined mostly by sand particles with some clay to provide structure and fertility. the sand particles are easily visible and the soil holds structure but breaks apart easily.

2. scott sand can improve his soil quality by incorporating more silt and organic matter into the soil. peat moss and organic matter can also be incorporated.