Which of these animal groups was not present by the end of the cambrian? bryozoans arthropods chordates mollusks

The organelle pictured is found in cells of and is theorized to have once been an independent organism.

Agroup of plant cells was exposed to radiation, which damaged the chloroplasts and caused them to lose function. if the mitochondria were unharmed, what would happen to the overall function of the plant cells? a. the cells would not be able to make food, but would be able to release energy from biomolecules. b. the cells would not be able to replicate dna, but would be able to break down waste. c. the cells would not be able to break down waste, but would be able to replicate dna. d. the cells would not be able to release energy from biomolecules, but would be able to make food.

When listening the levels of orginization in orginisims from the smallest to most complex , which level is just below organs in complexity