Answer: C) H2O Explanation: The common greenhouse gas containing only hydrogen and oxygen is H2O, this is water vapor. The common greenhouse gases are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. The composition (chemical formula) of those gases are: Water vapor: H2OCarbon dioxide: CO2Methane: CH4Nitrous oxide: NOOzone: O3. As you see the only one of those that contains only hydrogen and oxygen is H2O, water vapor.

Answer: D) 51 Explanation: Unit digit of this expression is always 1 as the base ends with 1.  For the tenth place digit we need to multiply the digit in the tenth place of the base and unit digit of the power and take its unit digit. i.e, tenth place digit in 2151 is 5 and tenth place digit in power 415 is 1 And the units digit in the product of 5 x 1 = 5   Therefore, last two digits of 2151415 is 51.

Answer: C) June 21 Explanation: The World Hydrography Day (WHD) is observed every year on June 21 to publicise the work of hydrographers and to create awareness about hydrography which is an essential science before undertaking any activity on or under the sea. The 2017 theme is “Mapping our seas, oceans and waterways – more important than ever”.

Answer: D) JXK 12L Explanation: The four women seem to agree that the plate starts out with the letter J. Three of them agree that the plate ends with 12L. Three of them think that the second letter is X, and a different three think that the third letter is K. The plate description that has all of these common elements is D.

Answer: D) Thermosphere Explanation: Most important weather phenomena occur in the layer of Thermosphere. Most of the weather phenomenon occur in the layer of Troposphere.

Answer: C) Soda Explanation: Here Soda is a Heterogenous Mixture.   A Heterogeneous Mixture is a mixture having a non-uniform composition i.e, the mixture contains components in different phases. Using various means, the parts in the mixture can be separated from one another.

The smallest unit of data storage in a computer is called Bit (Binary Digit). Half a byte (four bits) is called a Nibble.   1 bit (binary digit) = the value of 0 or 1 8 bits = 1 byte 1024 bytes = 1 kilobyte 1024 kilobytes = 1 megabyte 1024 megabytes = 1 gigabyte 1024 gigabytes = 1 terabyte 1024 terabytes = 1 petabyte   Hence, Computer storage units smallest to largest i.e, in ascending order is  1 bit  <  1 byte  <  1 KB  <  1 MB  <  1 GB  <  1TB  <  1 PB.

Answer: D) haemoglobin Explanation: Oxygen in our blood is transported by a protein named Haemoglobin.