Ascientist thinks he has discovered a drug that interferes with the functioning of a virus in the human body. to effectively block infection the drug can? a- weaken viral respiration. b- destroy viral mitochondria. c- reduce the ability of the virus to absorb cells. d- prevent the virus from entering cells.

The control of virus infection is complicated compared to bacteria since the virus   either enters into the host cells or used the host cell components to create new cells that is released to affect new cells. Hence it has been a challenge to isolate the virus particle and affect them with chemical components without causing damages to the host cells.

Hence antivirals are drugs that are designed to inhibit their activity. They will block the activity of the virus from entering the cells and make them into host. Hence D is the right option

poor water quality affects most estuarine organisms, including commercially important fish and shellfish. the pollutants that have the greatest impact on the health of estuaries include toxic substances like chemicals and heavy metals, nutrient pollution (or eutrophication), and pathogens such as bacteria or viruses.

organ system-an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.