Often, toward the beginning of romantic relationships, we experience whereas after the relationship has continued for a number of years, we experience

 The correct answer is :  passionate love ;  companionate love

Explanation:  Passionate love is the intense yearning we feel for someone and that is accompanied by a physiological excitement, if this feeling is reciprocal we feel much satisfaction and ecstasy, but when this does not happen we feel sadness and despair. Compassionate love are feelings of intimacy and affection that we feel for a person but are not accompanied by passion or physiological excitement.

using the bering strait was the best transportation system.