Final answer:
The growth of Buddhism in Central Asia was halted by the invasion of the Huns, fierce nomadic warriors who overran the region after the fall of the Kushan Empire in 375 CE.
Step-by-step explanation:
The group of invaders that halted the growth of Buddhism in Central Asia were the Huns. These fierce nomadic warriors from the central Asian steppes emerged as a significant force in the late fourth century CE. Their swift westward expansion forced many tribes into Roman territories, sowing chaos and contributing to the decline of the Roman Empire.
This turmoil also affected the spread of Buddhism. After the fall of the Kushan Empire in 375 CE, which had been a major stabilizer for trade and cultural growth along the Silk Roads, Central Asia faced a period of instability. The Sogdians later controlled the region, but the powerful presence of the Huns disrupted the previously flourishing Buddhist traditions and monastic systems throughout Central Asia.
Subsequent histories saw other invaders and different religious influences, such as the spread of Islam, which replaced Buddhism as the dominant religion in many parts of Central Asia. The Buddhist monastic community faced destruction and suppression, forcing adherents to migrate or adapt to the changing religious landscape.