It would of course be ATP (Adenosine Tri Phosphate) the main source of energy for most cells.
Birds have beaks and not teeth
The proprioceptors are the sensors in the limbs, which give information regarding the muscle length, joint angle, and muscle tension that is combined to provide knowledge regarding the alignment of the limb in space. The muscle spindle is one of the kinds of proprioceptor, which gives information regarding the changes in the length of the muscle.
On the other hand, a nociceptor refers to a sensory neuron, which reacts towards the potentially damaging or destructing stimuli by conducting probable danger signals towards the brain and the spinal cord.
Proprioceptors are to reflex actions as nociceptors are to pain perception.
1) pathogen enters body and releases chemoattractants
2) a phagocyte/macrophage is attracted by these chemicals
3) the phagocyte engulfs the pathogen using its pseudopodia
4) the membranes of both organisms fuse forming a phagosome
5) lysosomers in the phogocyte fuse with the phagosome, forming a phagolysosome
6) these enzymes digest the pahogen (hydrolyse the bonds)
7) the antigens of the pathogen are placed on the surface of the phagocyte making an APC (antigen presenting cell)