Why does your heart never tire of constantly beating to pump blood throughout your body?

Mark's girlfriend dropped him off at a party, and then she went to visit her best friend two blocks away. when mark called his girlfriend to get a ride home, he could tell she had been drinking. what is mark's best plan of action? ride home with someone else and let his girlfriend drive herself get a friend to take him to his girlfriend's car so he can drive them both home ask his girlfriend to drive to the party, and then mark will drive them both home let his girlfriend drive them home slow to avoid getting pulled over

Viruses use the host's machinery to make copies of themselves. however, some human viruses require a type of replication that humans do not normally have. for example, humans normally do not have the ability to convert rna into dna. how can these types of viruses infect humans, when human cells cannot perform a particular role that the virus requires? a) the virus causes mutations in the human cells, resulting in the formation of new enzymes that are capable of performing these roles.b) the viral genome codes for specialized enzymes not in the host.c) the virus infects only those cells and species that can perform all the replication roles necessary.d) viruses can stay in a quiescent state until the host cell evolves this ability.

How do you imagine the heart of a person with prolonged high blood pressure might look different from the heart of someone with normal blood pressure?