Unlike the atmosphere today, the atmosphere 3.5 billion years ago did not

Unlike the atmosphere today, the atmosphere 3.5 billion years ago did not contain... ozone

CARBON MONOXIDE im only in middle school but that is my best guess

The fibers contract to produce tension on the associated tissues or tendons. Muscle tissue is enclosed in facia, which in turn is attached to other structures including ligament. There are three types of muscle tissues : skeletal, cardiac and smooth muscles.