In which situation are you likely to find a trait with only one allele?

If the expression of a trait requires only one copy of a gene (one allele), that trait is considered dominant. If the expression of a trait requires 2 copies of a gene (2 alleles), that trait is considered recessive. One exception is X-linked disorders.

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.