Check
match term definition

c
mold fossils a) formed when remains are trapped in tree sap

d
cast fossils b) preserved remains that are transformed into rock

f
trace fossils c) a raised fossil that has filled in the impression from a mold

b
petrified fossils d) impressions from very thin objects that were trapped in mud that was transformed into rock

e
imprint fossils e) preserved records of life, for example, a footprint or a trail

a
amber fossils f) formed when the remains of living things trapped in rock break down and leave a depression

Which are reasons cells undergo cell division?

Which prefix mean under less or below

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?