Answer: density
Convection is the circular cycle of rising and falling of a liquid or gas as it becomes hotter or cooler. When a liquid or gas becomes hotter, its density decreases, which causes the substance to rise. After rising, the substance loses heat and becomes cooler, which increases its density. This causes the substance to fall or sink to the bottom.
<span>simple distillation ur welcome :)</span>
Answer:
Decrease in water/oxygen levels of the aquatic environment
Explanation:
<u>The environmental pressure that would cause primitive fish to adopt the genetic capacity to live on land would be a decrease in water levels of the aquatic environment.</u>
A constant decrease in water level that keeps exposing the fish to dry land will enable natural selection to start selecting for traits that will enable them to survive on land, especially, the development of lungs in the place of gills, the capacity to walk instead of swimming, and the capacity to avoid desiccation.
<em>A decrease in water level will mean a decrease in the amount of oxygen available for gill's respiration. Respiration is an important process for any organism to stay alive. </em>
<em>A decrease in water level also means an exposure to sun. The heat from the sun could cause death by desiccation.</em>
<em>A decrease in water level means that movement (through swimming) will be limited. Movement is necessary for feeding and other biological activities.</em>
We base hypothesis or theories off of data or observations.
