Different periods in human history are named for the materials used to make tools. dr. franklin is searching through layers of soil, looking for tools made by humans. after screening the top layer of soil, he uses a magnet to speed up the search.
which type of location is dr. franklin most likely searching?
a. a cave from before the stone age
b. a stone age cave a
c. bronze age battle site
d. an iron age farm

Photosynthesis converts solar energy into what type of energy?

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?

Por qué crees que los huevos con cáscara se llaman amnióticos?