Anyone know how to do it or explain how to do it I’m so lost

When analyzing tree rings, what do scientists assume a thin ring indicates?

Use the phylogenetic tree to the right to determine which statement below is true. organisms a and f are not related. organism e is more closely related to organism b than organism f. organisms c and d are more closely related than organisms a and b. phylogenetic trees

The sea slug that considered to be a photosyntheesizing animal