Answer:
There are eight major terrestrial biomes: tropical wet forests, savannas, subtropical deserts, chaparral, temperate grasslands, temperate forests, boreal forests, and Arctic tundra. ... Other biomes, such as deserts and tundra, have low primary productivity due to extreme temperatures and a shortage of available water.
Explanation:
Pharyngeal constrictor muscles (superior, middle and inferior)
The pharyngeal constrictor muscles are a group of muscles that form the lumen of the pharynx. After you swallow, an act that you have control, it starts a involuntary contraction by these muscles to propel the bolus downwards.
