An ion which has lost two electrons has a charge of: 0 -2 +2 -6

The cluster of developing cells from conception until birth is called an

In the united states there are strict fishing seasons and limits, but not all countries enforce similar laws. in bangladesh there are few if any fishing restrictions. what might be the reason for less restrictions in smaller countries like bangladesh? a) the united states is the only country worried about overfishing. b) the united states wants to limit the supply of fish to increase the price. c) bangladesh and smaller countries have an unlimited supply of fish in their coastal waters. d) small countries, such as bangladesh, are practicing subsistence fishing, taking only the fish needed to survive.

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?