What type of circulatory system is present in humans?

The potential energy between two atoms in a molecule is given by $U(x) = \frac{a}{x^{12}} - \frac{b}{x^6}$,where $a$ and $b$ are positive constants and $x$ is the distance between the atoms. The atoms are in stable equilibrium when:

Three rods of the same dimensions have thermal conductivities $3 K, 2 K$,and $K$. They are arranged as shown in the figure below. The temperature of the junction in the steady state is:

$A$ charged particle of mass $m$ and charge $q$ is released from rest in a uniform electric field $E.$ Neglecting the effect of gravity,the kinetic energy of the charged particle after $t$ seconds is:

Which one of the following ecosystem types has the highest annual net primary productivity?

The angle between the lines whose direction cosines satisfy the equations $l + m + n = 0$ and $l^2 = m^2 + n^2$ is