So... I have'nt done this since November, but hope this helps.
1. A
2. A or B (most likely A)
3.B
4.B
Prokaryotes are usually smaller than eukaryotes. They also don’t have a nucleus so DNA is in the cytoplasm. They also have no organelle membranes where as eukaryotes do. Domains of prokaryotes include Bacteria and Archaea, and all eukaryotes are in the domain Eukarya. Both can be free living, but only eukaryotes can be multicellular. Prokaryotes first appeared on earth about 3.5 billions then eukaryotes appeared about a billion years later. Etc....
Answer:
D. Valve.
Explanation:
These allow blood to flow through without flowing back.
