What is referred to by 'a hereditary unit'?

What is associated with: a heralded 1973 battle of the sexes ended 6 4 6 4 6 3 in her favor? Based on the clue 'a herd of animals being moved in a group', what is the answer? Based on the clue 'a herd of rare native red deer inhabits this count...', what is the answer? Based on the clue 'a herd of these animals loxodonta africana is stam...', what is the answer? Based on the clue 'a heriz is a persian one', what is the answer? Based on the clue 'a hero is brave in deeds as well as words is the m...', what is the answer? Based on the clue 'a hero of the battle of san jacinto mirabeau buona...', what is the answer? Based on the clue 'a hero to many he trained as a doctor in argentina...', what is the answer?