The Following Questions Refer to the Description and Figure Below

question 1

Multiple Choice

The following questions refer to the description and figure below.
The figure represents a cross section of the sea floor through a mid-ocean rift valley, with alternating patches of black and white indicating sea floor with reversed magnetic polarities. At the arrow labeled "I" (the rift valley) , the igneous rock of the sea floor is so young that it can be accurately dated using carbon-14 dating. At the arrow labeled "III," however, the igneous rock is about 1 million years old, and potassium-40 dating is typically used to date such rocks. NOTE: the dashed horizontal arrows indicate the direction of sea-floor spreading, away from the rift valley.
Figure 25.1
-Which free-living cells were the earliest contributors to the formation of Earth's oxidizing atmosphere?

• A)cyanobacteria
• B)chloroplasts
• C)mitochondria
• D)seaweeds
• E)endosymbionts

---

Definitions:

Attitudes

Behavioral inclinations demonstrated through assessing a specific entity with a level of preference or aversion.

Adapt

To adjust or change one's behavior or thinking to suit a new situation or environment.

Conditioned Stimulus

A neutral stimulus that, through repeated pairings with an unconditioned stimulus, comes to evoke a conditioned response.

Unconditioned Stimulus

A stimulus (e.g., meat powder) that naturally evokes a particular response (salivation).