Released STAAR Biology EOC · 2025 · Item 28 · 2 points
Walkthrough: Biology 2025, Item 28
B.9A · Evolution & Natural Selection · unscored study
Cytochrome c is a protein that helps release energy from food and is produced by nearly all organisms. The table shows a short sequence of the amino acids in cytochrome c for several species. Identify the organism that is MOST CLOSELY related to tuna AND explain your reasoning using evidence from the table.
| Organism | 9 | 10 | 11 | 12 | 13 |
|---|---|---|---|---|---|
| Tuna | Glycine | Aspartic acid | Valine | Alanine | Lysine |
| Chicken | Glycine | Aspartic acid | Isoleucine | Glutamic acid | Lysine |
| Neurospora | Glycine | Aspartic acid | Serine | Lysine | Lysine |
| Gray whale | Glycine | Aspartic acid | Valine | Glutamic acid | Lysine |
| Silkworm moth | Glycine | Asparagine | Alanine | Glutamic acid | Asparagine |
Response format: written short response (2 points).
1. Understand the question
Compare each organism's amino acids with tuna's at positions 9–13. Fewer differences mean a closer relationship.
Try the question on your own first, then reveal one step at a time.
2. Solve it step by step
Question, artwork, answer key and rationale: Texas Education Agency released STAAR test. Walkthrough steps written by TEKSForge. Studying here does not change your mastery or scores.