Based on the phylogenetic tree in Figure 28.2, which of the following statements is correct? a. The most recent common ancestor of Excavata is older than that of SAR. b. The most recent common ancestor of SAR is older than that of Unikonta. c. The most basal (first to diverge) eukaryotic supergroup cannot be determined. d. Excavata is the most basal eukaryotic supergroup.

Verified step by step guidance

1. Step 1: Understand the question. The question is asking you to interpret a phylogenetic tree and determine which statement is correct based on the information provided in the tree.
2. Step 2: Review the phylogenetic tree in Figure 28.2. Look at the branching patterns and the relative positions of the groups mentioned in the question: Excavata, SAR, and Unikonta.
3. Step 3: Evaluate each statement. For statement a, determine if the most recent common ancestor of Excavata is older than that of SAR by looking at where these groups branch off from the tree. For statement b, do the same for SAR and Unikonta. For statement c, consider whether the tree provides enough information to determine which eukaryotic supergroup diverged first. For statement d, determine if Excavata is the most basal eukaryotic supergroup by looking at its position on the tree.
4. Step 4: Compare your evaluations of each statement to the information in the phylogenetic tree. The correct statement will accurately reflect the relationships and divergence times shown in the tree.
5. Step 5: Choose the correct statement based on your evaluations. Remember that the correct statement must be supported by the information in the phylogenetic tree.