Which statement best describes the law of conservation of energy?
o
a. the total energy in an open system can only increase.
b. energy cannot be created or destroyed.
c. energy cannot change forms.
o
o
d. the total energy in a dynamic system can only decrease.

The correct option is B.  Energy cannot be created or destroyed.

Explanation:

The law of conservation of energy states that energy can neither be created nor be destroyed. However, energy can change from one form to another.

Hence, in a system energy might change forms but the total energy on Earth remains the same.

In a food chain, most of the energy is lost as heat. But it still is a form of energy. Hence, energy is neither created nor destroyed, it only changes forms.

Scientists used gene therapy to restore the sight of the dogs who suffer from inherited blindness.

Inherited blindness is identified as retinitis pigmentosa. It is the progressive loss of both the rods and the cones photoreceptors in the retina from the edge of the retina to the centre, leading to worsening tunnel vision caused by the loss of peripheral sight

A human gene that enabled cells in the retina to become sensitive to light is added into the retina cells. The scientists then inject a chemical called "photoswitch" in the eye. It attaches itself to the ion channel protein and enables the full conversion of light into an electrical signal relayed to the brain.