Answer: C) Pedro Cabral Explanation: In April 1500, Brazil was claimed by Portugal on the arrival of the Portuguese fleet commanded by Pedro Alvares Cabral.

Answer: A) 50 days Explanation: 50 men can build a tank in 40 days  Assume 1 man does 1 unit of work in 1 day Then the total work is 50×40 = 2000 units   50 men work in the first 10 days and completes 50×10 = 500 units of work 45 men work in the next 10 days and completes 45×10 = 450 units of work 40 men work in the next 10 days and completes 40×10 = 400 units of work 35 men work in the next 10 days and completes 35×10 = 350 units of work So far 500 + 450 + 400 + 350 = 1700 units of work is completed and   Remaining work is 2000 - 1700 = 300 units   30 men work in the next 10 days. In each day, they does 30 units of work.   Therefore, additional days required = 300/30 =10   Thus, total 10+10+10+10+10 = 50 days required.

Answer: B) B Explanation: The receptor molecules, which receive signals from outside the cell, passing the signal to the inside.   In order for a nerve cell, or any cell, to perceive its environment, it needs a sensory apparatus. And for an individual cell, most of that sensation is derived at the cell surface. So, it expresses on its cell surface proteins that span across the membrane. In the outside world, these proteins can act to receive signals, catching molecules on the outside and then as the molecule passes to the inside of the cell, they can send signals like alarm signals that can tell the cell that a particular molecule is outside.   Hence, here B is the receptor cell.