Which of the following crops produces recalcitrant seeds?

What type of nutrition do fungi exhibit?

Which of the following statements is false regarding the properties of electromagnetic waves?

Four resistors $A, B, C$ and $D$ form a Wheatstone bridge as shown in the figure. The bridge is balanced when $C = 100 \Omega$. If $A$ and $B$ are interchanged,the bridge balances for $C = 121 \Omega$. The value of $D$ is (in $\Omega$)

The potential difference between two parallel plates is $10^4 ~V$. If the plates are separated by $0.5 ~cm$,the force on an electron between the plates is

Check whether the following pair of statements are negations of each other. Give reasons for your answer.
$I$: $x+y=y+x$ is true for every real number $x$ and $y$.
$II$: There exists real numbers $x$ and $y$ for which $x+y \neq y+x$.