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 <span>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
</span>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 <span>ion channel protein and enables the full conversion of light into an electrical signal relayed to the brain.</span>
<span>Laryngotracheobronchitis or croup is a disease that caused by viral infection. The virus could be influenza or parainfluenza virus. The infection will cause edema of the trachea and might obstruct the airway, causing difficulty in breathing.
</span>In this case, nurse should take attention to the patient airway and breathing. Patient with dypneu should be given oxygen and racemic epinephrine nebulized. Corticosteroid also help to reduce the swelling such as dexamethasome or budesonide inhalation.
Answer:
D: A density-independent factor.
Explanation:
An earthquake is a density-independent limiting factor