Which of the following statements is true? During sublimation, a plasma changes directly into a solid. The nucleus of an atom is made of protons and neutrons. The boiling point of a substance is dependent of volume. Electrons orbit the nucleus of an atom in straight lines.

This is the main structural axis of the plant that supports leaves, flowers and fruits; transports fluids; stores nutrients and produces new tissue.

Consider the venn diagram of plant reproduction. where in this image, areas a - d, would you insert the picture of the orange lily?

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?