Given below is the $ECG$ of a normal human. Which one of its components is correctly interpreted below?

Which of the following statements is correct?

$A$ man weighing $60\, kg$ stands on the horizontal platform of a spring balance. The platform starts executing simple harmonic motion of amplitude $0.1\, m$ and frequency $\frac{2}{\pi }\, Hz$. Which of the following statements is correct?

If ${}^n C_{r-1}=330$,${}^n C_r=462$,and ${}^n C_{r+1}=462$,then $r$ is equal to

Consider the following statements. Which of the following statements are correct?
$(i)$ Froth floatation technique is used to concentrate sulphide ore.
$(ii)$ Froth floatation technique is based upon differential wettability of ore and impurity in water.
$(iii)$ Red Bauxite is concentrated by Bayer’s process.
$(iv)$ Carbon is used as reducing agent during extraction of zinc from zinc blende.

Match the items given in Column $I$ with those in Column $II$ and select the correct option given below:

Column $I$	Column $II$
$(a)$ Tidal volume	$(i)$ $2500 - 3000 \ mL$
$(b)$ Inspiratory Reserve volume	$(ii)$ $1100 - 1200 \ mL$
$(c)$ Expiratory Reserve volume	$(iii)$ $500 - 550 \ mL$
$(d)$ Residual volume	$(iv)$ $1000 - 1100 \ mL$