The common Indian bullfrog is:

Which one of the following pairs of gases are the major cause of 'Greenhouse effect'?

The compound formed on heating chlorobenzene with chloral in the presence of concentrated sulphuric acid is:

Which of the following components provides a sticky character to the bacterial cell?

Reduction in $pH$ of blood will

Which of the following statements are true regarding Bohr's model of the hydrogen atom?
$(I)$ Orbiting speed of the electron decreases as it shifts to discrete orbits away from the nucleus.
$(II)$ Radii of allowed orbits of the electron are proportional to the principal quantum number.
$(III)$ Frequency with which electrons orbit around the nucleus in discrete orbits is inversely proportional to the cube of the principal quantum number.
$(IV)$ Binding force with which the electron is bound to the nucleus increases as it shifts to outer orbits.
Select the correct answer using the codes given below.