Question : Which of the following animals have a single opening in their digestive system that serves both as a mouth and an anus?

Option 1: Arachnids

Option 2: Echinoderms

Option 3: Platyhelminthes

Option 4: Arthropods

Question : How many anions surround a sodium ion in a crystal lattice of sodium chloride?

Option 1: Six

Option 2: Eight

Option 3: Seven

Option 4: Nine

Question : Comprehension:

Read the passage and answer the questions that follow.

The drainage systems of India are mainly controlled by the broad relief features of the subcontinent. Accordingly, the Indian rivers are divided into two major groups: the Himalayan rivers; and the Peninsular rivers.
 

Apart from originating from the two major physiographic regions of India, the Himalayan and the Peninsular rivers are different from each other in many ways. Most of the Himalayan rivers are perennial. It means that they have water throughout the year. These rivers receive water from rain as well as from melted snow from the lofty mountains. The major Himalayan rivers are the Indus, the Ganga, and the Brahmaputra. These rivers are long and are joined by many large and important tributaries. A river along with its tributaries may be called a river system. The two major Himalayan rivers, the Indus and the Brahmaputra originate from the north of the mountain ranges. They cut through the mountains making gorges in the upper course. The perennial Himalayan rivers have long courses from their source to the sea. They perform intensive erosional activity in their upper courses and carry huge loads of silt and sand with their swift current. In the middle and the lower courses, these rivers form meanders, oxbow lakes, levees, and many other depositional features in their floodplains as their speed slackens. They also have well-developed deltas.
 

A large number of the Peninsular rivers like the Godavari, Kaveri, and Krishna are seasonal, as their flow is dependent on rainfall. During the dry season when it doesn’t rain, even the large rivers have reduced flow of water in their channels. The Peninsular rivers have shorter and shallower courses as compared to their Himalayan counterparts. However, some of them originate in the central highlands and flow towards the west. Most of the rivers of peninsular India originate in the Western Ghats and flow towards the Bay of Bengal.

Question:

‘Perennial’ rivers mean:

Option 1: receiving water from the rains

Option 2: those that originate in the mountains

Option 3: rivers with a long course

Option 4: full of water throughout the year

Question : If $\tan \theta=\frac{8}{15}$, then the value of $\sqrt{\frac{1-\sin \theta}{1+\sin \theta}}$ is:

Option 1: $\frac{1}{5}$

Option 2: $\frac{3}{5}$

Option 3: $\frac{2}{5}$

Option 4: $\frac{4}{5}$