Adenosine triphosphates glycogen I believe
Flatworms absorb oxygen by diffusion mechanism through their
skin to the cells in their bodies. Since flatworms do not have a circulatory system,
their bodies' cells are positioned close to the skin to ease the uptake of
oxygen from surrounding fluids or water.
The intermediate color or rather condition, in this case "roan", is a result of two alleles being codominant. Codominance occurs when the phenotype (or the physical expression of the gene) of a heterozygote individual expresses both the alleles in a pair of genes. In the given situation, both parents are homozygotes.