Taxon is a

Which disease in tobacco was identified by $D.J. Ivanowsky$ as being caused by viruses?

During embryonic development,the establishment of polarity along anterior/posterior,dorsal/ventral,or medial/lateral axis is called:

$A$ motorcyclist of mass $m$ is to negotiate a curve of radius $r$ with a speed $v$. The minimum value of the coefficient of friction so that this negotiation may take place safely,is

If $\alpha$ is a non-real root of the equation $x^6-1=0$,then $\frac{\alpha^2+\alpha^3+\alpha^4+\alpha^5}{\alpha+1}$ is equal to

If the lines represented by the equation $2x^2 - pxy + 2y^2 = 0$ are real,then the value of $p$ lies in the interval: