They build their pouch nest suspended within a clump of grass. Once enlarged, the cells clump together in clusters. Beyond that clump of trees was another clearing. This clump of platelets interacts with fibrin to form a platelet plug. McDade and his group walked across the clearing and into a clump of trees. Solids clump together to form the cud or bolus. In the centre of this hilltop was a clump of pines. "Polistes exclamans" clump in rather large aggregations while hibernating. Blinding is when wet material clump up and stick to the surface of the screen. With aging, these charges tend to reduce, and the fibres may clump together. Solids clump together to form the cud (or bolus). Transglutaminase binding of these proteins and peptides make them clump together. Quarks and gluons must clump together to form hadrons. He found that mixing incompatible types triggers an immune response and the red blood-cells clump. The surfactants also clump together on the surface and form a layer as shown below.