Based on your experience in the simulation, what do the numbers 3 and 4 refer to in 3NH4?

Which of the following statements is true? a. there are more chromosomes in an organism than there are genes. b. there are more genes in an organism that there are chemical bases. c. dna is made of sugar, phosphate, and carbon. d. genes are found in specific locations on a chromosome.

Asegment of dna that codes for rna and a protein is a

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?