人类活动正在加速许多野生动物的灭绝。

Human activities are accelerating the ___extinctions of many wildlife species.

许多语言正面临灭绝的危险。

Many languages are at risk of ___extinction.

气候变化可能导致许多物种的灭绝。

Climate change could lead to the ___extinctions of many species.

通过不给予奖励，狗对铃声的条件反射逐渐消退。

The dog's conditioned response to the bell gradually weakened through ___extinction without rewards.