Which of the following terms is used to refer to the number of varieties of plants and animals on Earth?

If $\vec F$ is the force acting on a particle having position vector $\vec r$ and $\vec \tau$ is the torque of this force about the origin,then:

In the interval $(-3, 3)$, the function $f(x) = \frac{x}{3} + \frac{3}{x}, x \neq 0$ is :

In a Young's double-slit experiment,the fringe width is $0.2 \, mm$. If the wavelength of light used is increased by $10\%$ and the separation between the slits is also increased by $10\%$,the fringe width will be.......$mm$.

In which interval is the function $f(x) = 2x^2 - \ln |x|, (x \neq 0)$ monotonically decreasing?

$A$ bar of cross-sectional area $A$ is subjected to two equal and opposite tensile forces at its ends as shown in the figure. Consider a plane $BB'$ making an angle $\theta$ with the length. The ratio of tensile stress to the shearing stress on the plane $BB'$ is