PLEASE HELP!! Match how far back in the earth's climate history we can learn about from each proxy.

Clam shells

Ice cores

World's oldest rocks

Tree cores

Ocean sediments

1. 150 million years ago

2. 800,000 years ago

3. 10,000 years ago

4. 200 million years ago

5. 3.8 billion years ago

The deserts of the sahara and australia are associated with

15 ! come and answer! a(n) disease is caused by a pathogen and can spread among organisms. a infectious b noninfectious c toxic d contaminated

Keeping in mind the life cycle of bacteriophages, consider the following problem: during the reproductive cycle of a temperate bacteriophage, the viral dna inserts into the bacterial chromosome where the resultant prophage behaves much like a trojan horse. it can remain quiescent, or it can become lytic and initiate a burst of progeny viruses. several operons maintain the prophage state by interacting with a repressor that keeps the lytic cycle in check. insults (ultraviolet light, for example) to the bacterial cell lead to a partial breakdown of the repressor, which in turn causes the production of enzymes involved in the lytic cycle. as stated in this simple form, would you consider this system of regulation to be operating under positive or negative control?