Final answer:
The false statement among the options is Osmoconformers are only found in marine environments. Although many osmoconformers are marine, they can also be found in other watery environments. The other statements about osmoconformers, marine vertebrates, marine invertebrates, and freshwater fish are factual.
So, the correct answer is E.
Step-by-step explanation:
Osmoconformers have bodily fluids with solute concentrations that are equal to those of their environment. While it is true that many osmoconformers are found in marine environments, there are exceptions, and they are not exclusively marine. For instance, some estuarine organisms can also be osmoconformers.
Statement a) is true as osmoconformers do have the same solute concentration as their environment, matching their internal conditions with the external environment. Statement b) is also true because marine vertebrates often excrete small volumes of concentrated urine as a means of conserving water and dealing with the osmotic challenges of a saltwater environment. Statement c) may seem false at first, but it is true that many marine invertebrates are in fact osmoregulators. They have to regulate their internal concentrations actively as they might not be isotonic with seawater. Statement d) is true because freshwater fish are hypertonic to their environment, meaning that they have higher solute concentrations in their body compared to the freshwater they live in, leading to water influx, which they manage by excreting diluted urine and actively taking in salts.
So, the correct answer is E.