Questions

If some action has started in the past and is still continuing, then present perfect continuous tense should be used instead of present continuous tense. So, the phrase ‘is working’ needs to be replaced with ‘has been working’ to make the sentence contextually correct. Thus, the correct formation would be, ‘Ramesh has been working in this factory for the past three months’.

A sinkhole (in Karst topography) is a hole in the ground that forms when water dissolves surface rock. Often, this surface rock is limestone, which is easily eroded, or worn away, by the movement of water.

Formation of a Sinkhole: In a landscape where limestone sits underneath the soil, water from rainfall collects in cracks in the stone. These cracks are called joints. Slowly, as the limestone dissolves and is carried away, the joints widen until the ground above them becomes unstable and collapses. The collapse often happens very suddenly and without very much warning. Water collects in these collapsed sections, forming sinkholes.

Sinkholes also form when the roofs of caves collapse. Sinkholes are often funnel-shaped, with the wide end open at the surface and the narrow end at the bottom of the pool.Sinkholes vary from shallow holes about 1 meter (3 feet) deep, to pits more than 50 meters (165 feet) deep.

The most common gas people breathe from clean air is nitrogen. Air is a mixture of gases, and the air on Earth contains about 78 percent nitrogen and about 21 percent oxygen. Argon, carbon dioxide neon, helium, methane, krypton, hydrogen and xenon are in much smaller amounts.

All   are   correct   except   4   as   a cloudburst  can  occur  anytime  and at  any  place  which  is  affected  by convective weather system.

Let the heights of Cat, Table and Turtle be C, T & R respectively.

From the above given figure,

C + T - R = 170 ......(a)

R + T - C = 130 ......(b)

Adding above eqns (a) & (b), we get

2T = 300

T = 150 cm

Hence, the height of the table is 150 cm.