PLEASE HELP pl
In addition to the heart, what other mechanism helps to circulate blood?

Which action is most likely to contribute to a positive self-image?

Which of the following can be effective in preventing the onset of viral infection in humans? a) taking vitaminsb) getting vaccinatedc) taking antibioticsd) taking drugs that inhibit transcription

Which of the following represents a difference between viruses and viroids? a) viruses infect many types of cells, whereas viroids infect only prokaryotic cells. b) viruses have capsids composed of protein, whereas viroids have no capsids. c) viruses have genomes composed of rna, whereas viroids have genomes composed of dna. d) viruses cannot pass through plasmodesmata, whereas viroids can.