a group of canadian researchers have discovered a set of genes that determine the lifespan of the common nematode. by manipulating the newly discovered genes, the team was abe to increase the lifespan of a nematode fivefold. altering the genes apparently caused the metabolism of the worms to operate at amore leisurely pace. this caused the dna effects thought to bring about aging to accumulate at a reduced rate. of course the cause of againg in humans are more involved than those in nematodes. however, researchers are confident that these discoveries will provide invaluable clues about the aging process and that they will allow science to eventually delay the process.

이 지문에서 those와 they가 가리키는 것이 각각 무어인지 알고싶어요.....
친절한 답변 꼭 부탁드리겠습니다 . ^^