Why is heartwood darker in color than sapwood?
a. heartwood is closer to the center of the stem; sapwood is away from the center of the stem.
b. heartwood does not conduct water; sapwood is active in fluid transport.
c. heartwood contains xylem tissue; sapwood contains phloem tissue.

Each pair of clay balls represents two planetesimals. if each planetesimal is composed of the same material and is separated he the same distance, which pair experiences the frayed gravitational attraction?

Part a - which gene to compare? in this exercise, you will use the cytochrome c oxidase i (coi) gene to investigate relationships among salmon species. (this gene encodes a protein that functions in the mitochondrial electron transport chain.) you will compare the coi gene sequences from your salmon test samples to the standard sequences for each salmon species. in order for the coi gene to be useful for distinguishing among the different salmon species, which three statements must be true?

Apopulation follows a period of decline; overshoot increase; overshoot increase; scarcity scarcity; dieback