Which of the following statements is/are true?

1. Enriched uranium is a type of uranium in which the percent composition of uranium-238 has been increased through the process of isotope separation. 2. ²³⁵U is the only nuclide existing in nature (in any appreciable amount) that is fissile with thermal neutrons.

Statement 1 is wrong: Enriched uranium is a type of uranium in which the percent composition of uranium-235 has been increased through the process of isotope separation. Statement 2 is correct: ²³⁵U is the only nuclide existing in nature (in any appreciable amount) that is fissile with thermal neutrons. To make any other isotope radioactive, we need to perform either fission or fusion (that means other isotopes aren't naturally available). Enriched uranium is a critical component for both civil nuclear power generation and military nuclear weapons.