Substances and mixtures are two types

Which best describes why nh4+ can form an ionic bond with ci-?

The human eye contains a molecule called 11-cis-retinal that changes shape when struck with light of sufficient energy. the change in shape triggers a series of events that results in an electrical signal being sent to the brain that results in vision. the minimum energy required to change the conformation of 11-cis-retinal within the eye is about 164 kj/mol.

What does the symbol (–hfus) indicate in a phase change?