Retinitis pigmentosa are a diverse group of hereditary diseases that lead to incurable blindness and affect two million people worldwide. Though the causes are diverse, the manifestation of the disease is similar: highly sensitive rod photoreceptors, which allow us to see at dusk, die first  and the cones that operate during daylight and are responsible for high-resolution color vision follow. 

Theories of physics rest on fundamental assumptions and those assumptions are based on how the real world works, and often produce amazingly precise predictions. 

The most comprehensive theory of elementary particles to-date, Quantum Field Theory, explains nature's electromagnetic, weak and strong nuclear forces (though not gravity).

Introduction

The use of non-human animal models has allowed the fast progression of scientific discovery over the last several centuries. These experiments have lead to great discoveries that have allowed for the alleviation of suffering, sickness, and disease in both humans and animals. Over the years there have been changes in the way we view the rights of animals that have lead to better treatment of models, and discoveries of methods that reduce the need for experimentation on animals. However, we have not yet reached the point that their use is not necessary. If the use of animals in experimentation is to continue, there are many ways of limiting and minimizing suffering while maximizing the benefit from their use.