Is the digestive system of flukes complete or incomplete?

Energy derived from hot rocks and fluids beneath the earth’s surface is

Acertain species of fish can have either long or short fins. the allele for long fins is dominant over the allele for short fins. a heterozygous, long-finned fish is crossed with a homozygous, short-finned fish. of the offspring, will have long fins and be , and will have short fins and be .

Whats one way that rocks do not follow the typical rock cycle pathway?