Knots in timber are

ANS:D - signs of branches cut off.

Knot- it shows the root branches which are broken or cut of the tree.

Shakes- It is the result of rupture of tissues causing partial or complete separation of the along grain.

Heat shake- it occurs due to shrinkage of the inner part of the trunk. They start from the heart, extend in a redial direction perpendicular to the annual rings.

Star shake- these are redial cracks start from the park and extend towards inner portion.

Cup shake or ring shake- they are curved cracks parallel to annual rings.