PBS Evolution: Great Transformations 1. If the world’s history were compressed into one hour, how long have humans been here?
Microbes. single-celled organisms
2. How long ago did mammals first appear on earth?
Mammals first appeared about 200 million years ago
3. What type of animal did the skull that Dr. Gingrich discovered resemble?
Dr. Gingrich discovered resembled a whale
4. What did “Whale Valley” used to be?
5. What unusual feature did they find at the end of the early tetrapods’ limbs?

6. How long ago did animals first appear on Earth?
About 800 million years.
7. When the mouse “eyeless” gene was implanted into the fruit flies, what happened?

8. How would walking on two legs be an advantage?

Most of the fossils found in virginia are in the coastal plain, valley, ridge, and appalachian plateau regions, best suggesting that these geographic provinces a) were once covered by seawater. b) are the oldest parts of virginia. c) have a great deal of karst topography. d) have large amounts of sedimentary rock.

Which statements about the fluid mosaic structure of a membrane are correct? select the three correct statements.which statements about the fluid mosaic structure of a membrane are correct? select the three correct statements.the framework of a membrane is a bilayer of phospholipids with their hydrophilic heads facing the aqueous environment inside and outside of the cell and their hydrophobic tails clustered in the center.because membranes are fluid, membrane proteins and phospholipids can drift about in the membrane.the diverse proteins found in and attached to membranes perform many important functions.the kinky tails of some proteins keep the membrane fluid by preventing the component molecules from packing solidly together.membranes include a mosaic, or mix, of carbohydrates embedded in a phospholipid bilayer.

The image below shows a common blood pressure gauge. what does this device do? a. measures the level of oxygen present in the blood b. measures the pressure of blood when the lungs expand and compress c. measures the electrical activity of the heart d. measures the pressure of blood when the heart contracts and relaxes