Answer: A) Terrace cultivation Explanation: Hence, soil erosion on hillslopes can be checked by Terrace cultivation.

Answer: A) Oxygen Explanation: A person or animal must take in oxygen for respiration to occur. A mouth (choice a) is not essential because breathing can occur through the nose. Choices b and d are clearly not essential and can be ruled out.

Answer: B) 7.5 min Explanation: B runs around the track in 10 min.  i.e ,    Speed of B = 10 min per round  Therefore,  A beats B by 1 round   Time taken  by A to complete 4 rounds    = Time taken by B to complete 3 rounds    = 30 min    Therefore, A's speed = 30/4 min per round = 7.5 min per round  Hence, if the race is only of one round A's time over the course = 7 min 30 sec

Answer: A) Arithmetic and Control unit Explanation:

Answer: B) 20 days Explanation: (5m + 9w)10 = (6m + 12w)8  => 50m + 90w = 48w + 96 w    => 1m = 3w 5m + 9w = 5m + 3m = 8m   8 men can do the work in 10 days. 3m +3w = 3m + 1w = 4m So, 4 men can do the work in (10 x 8)/4 = 20 days.

Answer: D) 20 years Explanation: Present total age of the members = 26(5) = 130 years.   Present age of the youngest member = 10 years   Present total age of the remaining four members = 130 -10 = 120 years   Their average age at the time of the birth of the youngest member = 120-4×104 = 30 - 10 = 20 years.

Answer: D) Gulf of California Explanation: A gulf in geography is a large bay that is an arm of an ocean or sea.   The second smallest sea on Earth is the Sea of Cortez, more commonly called the Gulf of California. This sea is about 62,000 square miles. It lies between Mexico and the Baja California Peninsula.

Answer: D) 2 hrs Explanation: Speed in downstream = 96/8 = 12 kmph Speed of current = 4 km/hr Speed of the boatman in still water = 12 – 4 = 8 kmph Speed in upstream = 8 – 4 = 4 kmph Time taken to cover 8 km upstream = 8/4 = 2 hours.