Sentence:  In spite of these qualifications, the broad distinction between <WSD>instinct</WSD> and habit is undeniable. To take extreme cases, every animal at birth can take food by instinct, before it has had opportunity to learn; on the other hand, no one can ride a bicycle by instinct, though, after learning, the necessary movements become just as automatic as if they were instinctive. 
Meaning of the word marked with <WSD> tags:  A natural or inherent impulse or behaviour.