Join the two sentences with who, that or whose
1) William Rees is a professor. He used the term "ecological footprint" in an academic paper.
2) Hans Lippershey was an eyeglass maker. He invented the microscope with two colleagues.
3) Legambiente is an italian association. It was created in 1980.
4) This is a teacher. His son is a famous biologist.
5) Enrico Fermi was an Italian-American physicist. He developed the first nuclear reactor.
6) Carbon dioxide is a natural gas. It's essential for life on Earth.