Which structure in the embryo is considered the precursor to the urinary bladder?

Which of the following cancers is caused by the consumption of tobacco?

If $\log (1+x) - \frac{2x}{2+x}$ is increasing, then

Three unequal resistors in parallel are equivalent to a resistance $1 \, \Omega$. If two of them are in the ratio $1 : 2$ and if no resistance value is fractional,the largest of the three resistances in $ohms$ is

Which of the following is an oxidizing agent?

If $a, b, c$ and $d \in \mathbb{R}$ such that $a^2+b^2=4$ and $c^2+d^2=2$ and if $(a+ib)^2=(c+id)^2(x+iy)$,then $x^2+y^2$ is equal to