The tides in sea are primarily due to _______. 

The correct answer is 1.

Key Points

• The periodical rise and fall of the sea level is known as tide.
• The Moon's gravitational pull is the major cause of a tide. Hence statement 2 is correct.
• Sun's gravitational pull and centrifugal force due to the gravitational pull of the earth to a lesser extent so causes types. Hence statements 1 and 3 are correct.
• The movement of water is caused by Meteorological effects like winds and atmospheric pressure change and is known as surges. 
• The tide generating force is the difference between the gravitational attraction of the Moon and the centrifugal force.  
• Tides vary in frequency, direction, and movement from place to place and from time to time.
• Based on frequency, they are classified into the semi diurnal, diurnal, and mixed tide.  
• Springtide: when the sun, moon, and earth are in a straight line the height of the tide is higher and this occurs on a full moon period.
• Neap tide: when the moon and the sun are at right angles to each other the forces of the sun and the moon tend to counteract each other.  It occurs twice a month.