A craton is a large, stable portion of Earth's lithosphere that makes up part of a continent. The Kaapvaal craton in Africa is one of five ancient cratons left from the Precambrian era. The rock has remained tectonically stable since its formation 3.6 billion to 2 billion years ago. What do you think the term "tectonically stable" means? Why do you think this rock formation is important to understanding the history of Earth? Do you think studying ancient rock formations such as the Kaapvaal craton can teach scientists not only about Earth's past but also its future? Why or why not?

Multicellular organisms use cell division, mitosis, for growth and the maintenance and repair of cells and tissues. single-celled organisms may use cell division as their method of reproduction. regardless of the reason for mitosis, the process ensures genetic continuity. what is the step in the cell cycle that ensure genetic continuity?

To maintain asepsis when administering an injection, all parts of the syringe can be handled except the:

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?