en_tn_condensed/mrk/12/21.md

the second ... the third

These numbers refer to each of the brothers and can be expressed as such. Alternate translation: "the second brother ... the third brother" (See: rc://en/ta/man/translate/figs-ellipsis)

the second took her

"the second married her." Here marrying a woman is spoken of as "taking" her.

the third in the same way

"the third brother married her as his other bothers had done, and he also died leaving no children" (See: rc://en/ta/man/translate/figs-explicit)

seed

This is a euphemism for a son. See how you translated this in verse 19. (See: rc://en/ta/man/translate/figs-euphemism)