Questions

The relative pronoun acts as the subject or object of the relative clause. It replaces words like she, he, him, her, they, them etc.

It is, therefore, wrong to repeat the pronoun in the relative clause.

Hence, the correct sentence is Shreya, who is my best friend, is a singer.

From the given data,

1 rabbit is going towards river not the six eephants. And these 6 elephants saw 2 monkeys are going towards river. Each monkey is holding 1 tortoice.

Hence, number of animals going towards river are 1 rabbit, 2 monkeys and 2 tortoice

= 1 + 2 + 2

= 5.

Godavari, India's second longest river after the river Ganga and is one among the peninsular rivers.

The river Godavari is often referred to as Vridha Ganga because of its large size and extent among the peninsular rivers.

90 D in a R A => 90 degrees in a Right Angle. 

This is similar to 

26 L of the A = 26 Letters of the Alphabet

12 S of the Z.

Yellow and green color mix make a Lime color.

The three primary colors in additive mixing are red, green, and blue. In the absence of color or, when no colors are showing, the result is black. If all three primary colors are showing, the result is white. When red and green combine, the result is yellow. When red and blue combine, the result is magenta. When blue and green combine, the result is cyan.