The last veda called the Atharva Veda is a collection of magic spells and charms to ward off the evil spirits and diseases. It is considered a non-Aryan work and is the latest addition to the Vedas in later Vedic age.
Viharas were for the purpose of living, Chaityas were assemblies for the purpose of discussions. Further, Chaityas were with Stupas, Viharas did not have stupas.
Heliodorus was the Greek ambassador of Indo-Greek king Antialcidas Nikephoros of Taxila in the court of Sunga King Bhagbhadra. He erected famous votive Heliodorus pillar around 110 BC near Vidisha, Madhya Pradesh.
EXAMIANS