Which of the following describes the molecular structure of the dna molecule? a. complimentary base pairing b. hydrogen bonding c. double helix d. x-ray crystallography

Which best describes how sediment forms? loose material is cemented by pressure. erosion breaks down rock and other material. molten rock cools above earth's surface. chemical changes cause sediment to compact together.

Match each law or principle to its description. 1. law of original horizontality sediment continues to spread in a flat plane until it hits an edge or runs out of material. 2. law of superposition the youngest strata are at the top and the oldest are at the bottom. 3. law of original lateral continuity sediment gets pulled down by gravity in a horizontal and flat layer. 4. law of cross-cutting or intrusive relationships if there is a fracture or intrusive feature seen in rock strata, it is younger than the rock strata.

The structure of cells has changed significantly overtime. what concept explains the presence of mitochondria in cells?