Which phase of the cell cycle is characterized by the replication of $DNA$ and the synthesis of histone proteins?

$A$ whistle $S$ of frequency $f$ revolves in a circle of radius $R$ at a constant speed $v$. What is the ratio of the largest and smallest frequency detected by a detector $D$ at rest at a distance $2R$ from the center of the circle as shown in the figure? (Take $c$ as the speed of sound.)

Which of the following is a part of the pistil (gynoecium)?

$A$ force applied by an engine on a train of mass $2.05 \times 10^6 \ kg$ changes its velocity from $5 \ m/s$ to $25 \ m/s$ in $5 \ minutes$. The power of the engine is (in $MW$)

If $(1, a)$ and $(b, 2)$ are conjugate points with respect to the circle $x^2+y^2=25$,then $4a+2b$ is equal to

If the equation $px^2 + (2 - q)xy + 3y^2 - 6qx + 30y + 6q = 0$ represents a circle,then the values of $p$ and $q$ are: