Read the following text about sharks, then answer the questions below.
Contrary to the common wisdom that sharks are instinct-driven "eating machines", recent studies have indicated that many species possess powerful problem-solving skills, social skills and curiosity. The brain- to body-mass ratios of sharks are similar to those of mammals and birds, and migration patterns in sharks may be even more complex than in birds, with many sharks covering entire ocean basins. However, shark behaviour has only begun to be formally studied, so there is much more to learn.
A popular myth is that sharks are immune to disease and cancer; however, this remains to be proven. The evidence that sharks are at least resistant to cancer and disease is mostly anecdotal and there have been few, if any, scientific or statistical studies that show sharks to have heightened immunity to disease.
According to the text, are the following statements true, false or not given?
- Research shows that sharks are more intelligent than most people think.
- Relative to their body size, sharks have bigger brains than birds.
- There is no real evidence proving that sharks are resistant to diseases.