Sometimes my pulse beat so quickly and hardly that i felt the palpitation of every artery; at others, i nearly sank to the ground through languor and extreme weakness. which definition of languor is most likely suited for this line?

somnolence; drowsiness

Explanation:

 The definition of languor that most likely suited for this line: "I nearly sank to the ground through languor and extreme weakness" is a feeling of tiredness or lack of strength, having a languid feeling, which is moving slowly and making very little effort. It is related to mental or physical tiredness or lack of activity, almost sleeping.

answer; teamwork;

answer (c) by causing social withdrawal;