Answer:
B
Explanation:
Sperm is produced in the testicles, eggs are produced in the ovaries.
Answer:
Pollution
Explanation:
<em>Burning of coal contributes most directly to an environmental change described as pollution.</em>
Pollution is generally defined as the presence of substance in the environment at a level that disrupt the normal biotic functioning of the environment. Pollutants are substances whose level of concentration in the environment affects the normal biotic functioning of the environment.
The burning of coal leads to the release of harmful substances to the environment. These substances could be in form of gases such as oxides of carbon, sulfur and nitrogen that are capable of causing acid rain and global warming, heavy metals such as mercury and lead, as well as particulate matters.
Heavy metals are harmful to organisms when they find their ways into the food chains while particulate matters in the atmosphere reduce visibility and are capable of causing damages to properties when they are deposited on them.
Ashes remains from coal burning are also capable of causing pollution to nearby lakes and water bodies when they are washed down. This will lead to the disturbance of lives in the aquatic environment and decrease the quality of the water bodies for various uses.
Answer:
C. Nucleic acid synthesis
Explanation:
AZT, azidothymidine, is an antiviral drug used to check the viral population by blocking the process of reproduction. The azidothymidin is particularly effective against human immunodeficiency virus (HIV) as this drug inhibits the activity of reverse transcriptase which is required for the formation of a DNA copy of the RNA genome of the virus.
Similarly, Valacyclovir is an antiviral drug that inhibits viral reproduction by blocking the DNA polymerases. The Valacyclovir serves as a prodrug of acyclovir.
Answer:
A
Explanation:
All involve the active transport of gases across membranes.
