Why is the arch shape and the keystone at the top of the arch a fitting analogy for what Robert Paine observed?

What occurs to the cell during mitosis

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?

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.