कौन सी नहर दक्षिणी जर्मनी में डेन्यूब और मेन नदियों को जोड़ने वाले एक प्रमुख आंतरिक जलमार्ग के रूप में उपयोग की जाती है?

Which of the following means of transport is the cheapest for carrying heavy and bulky goods over long distances?

Which port is recognized as the busiest port in the world in terms of total cargo tonnage and container throughput?

Which port closely follows Shanghai as the second busiest container port in the world?