The potato spindle tuber disease is caused by which of the following?

The value of $\cos \frac{2 \pi}{15} \cos \frac{4 \pi}{15} \cos \frac{8 \pi}{15} \cos \frac{14 \pi}{15}$ is :

$\int_0^\pi \frac{1}{1+\sin x} \, dx$ is equal to

The edible part of a tomato is . . . . . . .

An air bubble of radius $1 \ cm$ rises from the bottom portion through a liquid of density $1.5 \ g/cc$ at a constant speed of $0.25 \ cm/s$. If the density of air is neglected,the coefficient of viscosity of the liquid is approximately,(in $Pa \cdot s$):

Which one of the following gives Prussian blue colour?