What is the function of the algal component in a lichen?

The bond angle and hybridization in ether $(CH_3OCH_3)$ is

Bulk modulus of water is $2 \times 10^9 \ N/m^2$. The pressure required to increase the volume of water by $0.1 \%$ in $N/m^2$ is:

Which of the following is the strongest Lewis base?

Light of wavelength $\lambda$ is incident on a single slit of width $a$ and the distance between the slit and the screen is $D$. In the diffraction pattern,if the slit width is equal to the width of the central maximum,then $D$ is equal to:

Which of the following is a secondary pollutant?