1) Thermonuclear fusion in stars is a natural process, but artificial on Earth.
2) In the stars, the synthesis of the hydrogen isotope protium into helium occurs, and on Earth, in laboratories in thermonuclear fusion, deuterium, tritium, and lithium are used.
3) Thermonuclear fusion in stars is a self-regulating process, and on Earth, controlled thermonuclear fusion is still a major scientific problem.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.