The digestive system contains all four major tissue types, epithelial<span>, connective, muscle and nervous. e</span>pithelial<span> tissue lines the entire length the digestive tract. it is made up of many different types of cells, including goblet cells that secrete mucus.</span>
Answer:
Early land animals had both lungs AND gills, and their bodies consisted of few hard parts. Meaning they lacked things like an exoskeleton for instance. Animals today have either lungs OR gills and many have protecting hard parts of their bodies.
Explanation:
Answer:
depolarization leading to action potentials
Explanation:
The voltage-gated Na+ channels are responsible for rapid depolarization phase of the action potential. Action potential generation require depolarization of neuronal membrane which is acquired by influx of sodium ions through voltage gated sodium ion channels. If the Na+ channels are blocked, there will be no influx of sodium ions to cause depolarization hence action potential will not be generated.
Coral reefs<span> are also being degraded by many other factors. The list of problems can seem endless: overfishing, fishing using cyanide and dynamite, pollution from sewage and agriculture, massive outbreaks of predatory starfish, invasive species, and sedimentation from poor land use practices</span>