Hon placed aquatic plants in several test tubes that were filled with water. then, he placed half of the test tubes in a dark closet and the other half in a well-lit room. when he recorded his data, some of the plants had formed many small bubbles on the leaves, and some did not. which describes what hon most likely observed and the reason for these results?

Consider the model of the oxygen cycle on earth. the majority of earth's oxygen reservoirs are found in the a) atmosphere. b) biosphere. c) hydrosphere. d) lithosphere.

The same agricultural practices are used in every country of the world. select the best answer from the choices provided t f

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?