Which statement is true regarding schistosomes?

Schistosomes are a type of parasitic worm known for their ability to invade the tissues of their hosts. This characteristic is crucial to their life cycle and pathogenicity. Once schistosome larvae penetrate the skin of humans or other hosts, they migrate through tissues and eventually reach the blood vessels. In humans, schistosomes primarily inhabit the venous system, particularly around the intestines and urinary tract, and can cause significant damage by evading the host's immune response and inducing chronic inflammatory reactions.

In contrast, the other statements do not accurately describe schistosomes. For example, while they are often associated with water sources where they complete part of their life cycle, they are not restricted to aquatic environments alone. They do not inhabit exclusively the intestines; their adult forms reside in different locations within the host's circulatory system. Finally, schistosomes certainly affect humans, typically causing schistosomiasis, a disease characterized by various symptoms, including abdominal pain, diarrhea, and in severe cases, organ damage. Thus, the ability of schistosomes to invade tissue is a fundamental aspect of their biology and impact on human health.