A _____ arrow provides a visual clue to the relationship between two cells by pointing from the precedent cell to the dependent cell. The correct answer is Tracer. <span>By using this, it is easier to check the
accuracy of the formulas or the source of the errors, if there’s any.</span>
Answer: natural selection
HIV directly attacks CD4 helper lymphocytes directly. (D)
Answer: Baseball
Hope this helps!^^
1. Hydropower
2. Solar
3. Coal
4. Oil
5. Biomass