4. The basic structural and functional units of living tissues.
A. Cell
C. Oxygen
B. Cartilage
D. Muscle
-5. Which of the following is essential for organism to process carbon dioxide and water during
photosynthesis?
A. sunlight
B. oxygen C. soil D. chlorophyll
6. The following statements are challenges for the researchers in finding and identifying signs of
cells. Which is not part of the group?
A. Cells are microscopic and most have no parts to fossilize
B. Slightly younger rocks have been heated up and undergone other processes
C. Tectonic plate movements have destroyed nearly all rocks older than about 4 billion years.
D. Materials and testing laboratories are available
7. What unique substance do researchers look after in their study of eukaryotes?
A. biomarkers B. fossils
C. mitochondria
D. Stromatolites
8. Which of the following can be considered as a fossil?
A. a billion-year-old rock
B. a billion-year-old piece of amber
C. a billion-year-old amber with a primitive insect inside
D. the choices are all correct
9. Mainly the fossils are found on sedimentary rocks. What type of rocks are stromatolites?
A. igneous B. metamorphic C. sedimentary D. Trilobites​