Antrum is a characteristic feature of which follicle?

Male gametes are flagellated in

For the parabola $y^2+6y-2x+5=0$:
$(I)$ The vertex is $(-2,-3)$
$(II)$ The directrix is $y+3=0$
Which of the following is correct?

An inductor $(L = 100 \, mH)$,a resistor $(R = 100 \, \Omega)$,and a battery $(E = 100 \, V)$ are initially connected in series as shown in the figure. After a long time,the battery is disconnected by short-circuiting the points $A$ and $B$. The current in the circuit $1 \, ms$ after the short circuit is:

$A$ random variable $X$ has the following probability distribution:

$X = x_i$	$-2$	$-1$	$0$	$1$	$2$
$P(X = x_i)$	$\frac{1}{6}$	$k$	$\frac{1}{4}$	$k$	$\frac{1}{6}$

The variance of this random variable is:

The coefficient of $x^k$ in the expansion of $\frac{1-2x-x^2}{e^{-x}}$ is