The retina contains the photoreceptors known as the and .
It is there that the actual process of transduction occurs when the photoreceptors excite the cells
which in turn send the message on to the cells whose axons make up the optic nerve.
The information will then travel to the , which is the sensory switchboard within the brain and end up in the lobes where the information is processed specifically within the primary cortex .

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.

bradykinin is a physiologically and pharmacologically active peptide of the kinin group of proteins, consisting of nine amino acids.