Match the organism with the characteristic:
a. plant - like organisms that can be either unicellular or multicellular, and derive energy via photosynthesis
b. acellular microorganisms that require a host to reproduce
c. multicellular parasitic worms
d. unicellular organisms with complex cell structures; most are motile
1. Protozoa
2. Algae
3. Helminths
4. Viruses