Cell - structure and functions — Science STD 8 — Question

Large scale deforestation leads to the decrease in the amount of gas A in the atmosphere whereas the amount of gas B increases. The increased amount of gas B in the atmosphere causes an effect C which leads to excessive heating of the earth and its atmosphere producing an undesirable phenomenon D. What is A, B, C and D?

Name the characteristic of sound which can distinguish between the 'notes' (musical sounds) played on a flute and a sitar (both the notes having the same pitch and loudness).

Which synthetic fibre contains the organic group similar to those which give fruits their sweet smell?

Name any two special chemicals which are used as food preservatives.

Why does the shape of an ointment tube change when we squeeze it?

Which type of friction comes into play when a book kept on cylindrical pencils is moved by pushing?

Which of the following fuels has the highest calorific value?
Kerosene, Wood, Hydrogen, Cow-dung cakes, LPG

What term is used for ‘bulges’ observed on the sides of the body of Hydra?

State whether the following statements are True or False:
Internal fertilization takes place in hens.

What is the full form of LPG?