Asko Parpola and Michael Witzel both argued that these people were Iranians who came to the subcontinent before the Indo-Aryan migrations. For 10 points each:
[10h] Give this Rigvedic term for presumably native peoples of India who are defeated by the Aryan culture.
ANSWER: dāsa [or dasyu; or dasyūḥ; or dasyavaḥ; or dāsāh; or dās]
[10m] The dāsas may or may not have had a connection with a culture named for Margiana and this Central Asian region. The Indo-Greek Yavana kingdom was founded by invaders from this region, led by the Diodotids.
ANSWER: Bactria [or Bactriana; or Bāhlīka; or Bakhlo; or Bakhdi; or Greco-Bactrian Kingdom]
[10e] Dāsas were often marked by not engaging in this practice, which was done to a horse in Vedic culture as ashvamedha (“ush-vuh-MAY-duh”). Fire is a major component of this general kind of religious rite practiced by Brahmin priests.
ANSWER: sacrifice [accept word forms such as sacrificial; accept yajna]
<Benjamin McAvoy-Bickford, Other History>