Calcium, IP3, and cyclic AMP are all small molecules that can be found inside most cells, yet they are known to be important second messengers that can increase or decrease in response to a wide variety of signals. However, each signal often produces completely different responses. Give an example of this phenomenon, and explain how such responses occur.

they are second messenger molecules capable of triggering different signaling pathways

Explanation:

Second messenger molecules are intracellular signaling molecules that trigger different cellular responses. Examples of second messengers include Calcium ions (Ca2+), Inositol trisphosphate (IP3), and cyclic AMP (cAMP). Secondary messengers may be activated by different cellular responses, for example, cyclases that synthesize cAMP or by opening calcium ion (Ca2+) channels. For example, cAMP signaling is able to activate kinase enzymes that perform phosphorylation and interact with other effector molecules to mediate different biological functions (for example, regulation of glycogen and sugar metabolism). On the other hand, Ca2+ signaling is required for muscle contraction, neurotransmitter release, etc. Ca2+ signaling is known to exert allosteric control over enzymes and other types of proteins.

currents is the correct answer.

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.