When is 'World Nature Conservation Day' celebrated every year?

Sum of the factors of 4b²c²-(b²+c²-a²)² is : 

Find the value of a and b if (x-1) and (x+1) are factors of x⁴+ax³-3x²+2x+b

Identify the best way to improve the Bold part of the given sentence. If there is no improvement required, select ‘no improvement’-

Shyamalan’s movie ‘The Sixth Sense’ starring Bruce Willis was a great success but doesn’t win all Academy Award as expected.

Identify the best way to improve the Bold part of the given sentence. If there is no improvement required, select ‘no improvement’-

It take me within 15 minutes to walk to the metro station from my house.

Identify the segment in the sentence which contains the grammatical error.

Aanya’s class teacher and her friends congratulates her warmly when she won the inter school debate and brought the trophy to the school.

If a-b=1 and a³-b³=61, then the value of ab will be 

If p=99, then the value of p(p²+3p+3) will be