Which of the following key factors makes a plasmid a suitable vector in genetic engineering?

$A$ candidate takes three tests in succession and the probability of passing the first test is $p$. The probability of passing each succeeding test is $p$ if he passes the preceding one,or $\frac{p}{2}$ if he fails the preceding one. The candidate is selected if he passes at least two tests. The probability that the candidate is selected is:

Which of the following compounds forms silicones on hydrolysis?

The cathode of a photoelectric cell is changed from a work function $W_1$ to $W_2$ $(W_2 > W_1)$. If the photoelectric currents before and after the change are $I_1$ and $I_2$ respectively,and all other conditions remain constant,then which of the following is true? (Assume $hv > W_2$)

An object,moving with a speed of $6.25\, m/s$,is decelerated at a rate given by $\frac{dv}{dt} = -2.5\sqrt{v}$,where $v$ is the instantaneous speed. The time taken by the object to come to rest would be ........ $s$.

Let $A = \{ x: x \in R, |x| < 1 \}$ and $B = \{ x: x \in R, |x - 1| \ge 1 \}$. If $A \cup B = R - D$,then the set $D$ is: