The huge “Valles Marineris” (Mariner Valley) on Mars was formed by _____. The Grand Canyon on Earth was formed by _____.

Active water outflows on Mars are observed _____.

Water ice is able to survive near the _____ on the Moon and Mercury because it is _____ and there is no _____.

The thick muscular layer of the heart wall is called the and is responsible for .

Most oxygen is transported in the blood bound to to form .

The prevents backflow of blood into the right atrium during .

The flaplike covers the glottis during swallowing to prevent food from entering the .

According to the cash cycle model, which of the following will increase the firm’s minimum operating cash?

The stoppage of bleeding involves three mechanisms: , platelet plug formation, and .

The respiratory membrane consists of alveolar , capillary , and their fused .