Many scientific discoveries begin with direct observations. which could be a direct observation?
a. ants communicate by airborne chemicals
b. birds navigate by using magnetic fields
c. butterflies eat nectar from flowers
d. fish feel vibrations through special sensors
Answers: 1
Biology, 22.06.2019 05:50
Which of the organisms listed below performs nitrogen fixation? a. legumes b. plants c. bacteria d. fungi
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Biology, 22.06.2019 13:00
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?
Answers: 1
Biology, 22.06.2019 21:30
How can scientists use the fossil record to find evidence of relationships between different species?
Answers: 3
Many scientific discoveries begin with direct observations. which could be a direct observation?
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