While much information can be gleaned by testing the blood itself (drawn from a vein by phlebotomy), it is sometimes necessary to examine the source of the blood cells in the bone marrow to obtain more information on hematopoiesis; this is the role of bone marrow aspiration and biopsy.
From Wikipedia, the free encyclopedia. The wheel bug (Arilus cristatus), in the family Reduviidae, is one of the largest terrestrial true bugs in North America, being up to 1.5 inches (38 mm) in length. A characteristic structure is the wheel-shaped pronotal armor.
On a regular rear wheel, there are cogs on just one side of the hub â the drive side. On a flip-flop rear wheel, there is a single cog on either side of the hub (although you only use one at any given time). One of is a fixed cog, and the other is a freewheel. The freewheel body means that the rear wheel can turn even when youâre not pedaling. In a word, it allows you to coast. A Flip-Flop Hub (such as the one on the Montague Boston) has a cog on either side â one that is fixed and the other that freewheels. On a fixed gear, you canât coast. If the bike is moving, your legs need to be moving.