Two mathematicians have proved that a straightforward question—how hard is it to untie a knot?—has a complicated answer.

Genomes are key to unlocking life's evolutionary history. The presence and absence of certain genetic sequences and mutations ...

Add a pot beneath the tree by drawing an upside-down trapezoid shape.

Start by trimming the tree with your Christmas lighting of choice (you can never go wrong with warm lights, in my opinion), ...