Which of the following is a $C_4$ plant?

Calculate $\Delta H$ in $kJ$ for the following reaction:
$C_{(g)} + O_{2(g)} \longrightarrow CO_{2(g)}$
Given that:
$H_2O_{(g)} + C_{(g)} \longrightarrow CO_{(g)} + H_{2(g)} ; \Delta H = +131 \ kJ$
$CO_{(g)} + \frac{1}{2} O_{2(g)} \longrightarrow CO_{2(g)} ; \Delta H = -282 \ kJ$
$H_{2(g)} + \frac{1}{2} O_{2(g)} \longrightarrow H_2O_{(g)} ; \Delta H = -242 \ kJ$

Aluminium chloride exists as a dimer,$Al_2Cl_6$,in the solid state as well as in solutions of non-polar solvents such as benzene. When dissolved in water,it gives:

The electron affinity of sulfur is ...........

Assertion : The isothermal curves intersect each other at a certain point.
Reason : The isothermal change takes place slowly,so,the isothermal curves have very little slope.

During the mean life of a radioactive element,the fraction that disintegrates is