Which best describes viruses?
a. viruses are nonliving infectious agents.
b. viruses can replicate without a host cell.
c. viruses can be killed by strong antibiotics.
d. viruses are similar to bacterial cells

During endocytosis, cells expel what they don't need take in what they need shrink due to loss of water

How are proteins and nucleic acids related? they both provide energy. they both carry genetic information. the structure of proteins is determined by nucleic acids. the subunits of nucleic acids are also the subunits of proteins.

Astudy by solloch and et. al., in 2017, gives the map above which shows the frequency of alleles with a ccr5-delta32 mutations over 87 different countries. this mutation deletes the presence of a co-receptor (ccr5) on the outside of human t-cells (lymphocytes). some viruses, such as the one responsible for the black death and human immunodeficiency virus (hiv), require this receptor for attachment to host cells during the infection process. the black death was an epidemic that passed over northern europe during the 14th century killing nearly 60% of europeans. according to this information, which explanation best explains why northern europeans show a greater immunity for hiv than some other parts of the world?