Aragorn, the Rangers and life spans

[lathspell]

Aragorn is indeed through long lines connected to Elendil and therefore also to Elros, First King of Numenor! They received long life from the Valar for their aid in the War of Wrath, but were corrupted by Sauron! The Elendili survived and built the Southern and the Northern Kingdom until Sauron showed up again and destroyed many of these works. Then there was the Last Alliance and Sauron was overthrown once again and the Ring was taken.
That is why Aragorn had a longer life-span than other man, and to answer both questions: this quote is from appendix A, the last alinea of Eriador, Arnor, and the Heirs of Isildur and runs thus:

It is the pride and wonder of the Northern Line that, though their power departed and their people dwindled, through all the many generations the succession was unbroken from father to son. Also, though the length of lives of the Dúnedain grew ever less in Middle-earth, after the ending of their kings the waning was swifter in Gondor; and many of the Chieftains of the North still lived to twice the age of Men, and far beyond the days of even the oldest among us. Aragorn indeed lived to be two hundred and ten years old, longer than any of his line since King Arvegil, but in Aragorn Elessar the dignity of the kings of old was renewed.

The whole of Appendix A tells much more about the line of Isildur, Elendil's son, from the point where Isildur is betrayed by the Ring. So many more questions about this subject might find their answers there!

Hoping to have been of help,
lathspell