Answer: By studying the fossil record we can tell how long life has existed on Earth, and how different plants and animals are related to each other. Often we can work out how and where they lived, and use this information to find out about ancient environments. Fossils can tell us a lot about the past.
Transport of a substance from the lumen (cavity) of an organ into one side of a cell and out the other side of the cell into the extracellular fluid is called <u>transcellular transport</u>.
The two routes of transport of substances across the epithelium of the gut are by transcellular method and paracellular method.
Transcellular transport refers to the transport of solutes across a epithelial cell layer through the cells. The best example is the movement of glucose from the intestinal lumen to the extracellular fluid by the epithelial cells. The epithelial cells use the active transport to generate the transcellular transport. Active transport refers to the transport of substances from a region of its lower concentration to a region of its higher concentration against the concentration gradient using cellular energy.
Answer:
The correct option is b. lower esophageal sphincter
Explanation:
The esophagus is the initial part of the digestive tract and its function is the transport of the alimentary bolus from the pharynx to the stomach, through the thorax and avoid the reflux thereof. It begins and ends in two sphincter structures, the upper esophageal sphincter and the lower esophageal sphincter, which separate it from the pharynx and stomach. The lower esophageal sphincter has two functions: relax during swallowing and prevent reflux of the gastric contents into the esophagus in the postdeglutory period. After swallowing, there is a relaxation of the lower esophageal sphincter, pressure dropping to levels similar to those of the gastric fundus, which allows the bolus to enter the stomach. This relaxation lasts a few seconds and is followed by a strong contraction that prevents backflow of food.
Answer:
D
Explanation:
The cuticle of a plant helps protect its aerial epidermis from things like environmental stresses and desiccation.
Answer:
Q3:False, the oldest layers are found in the lower layers
Q2: A, a layer or a series of layers of rock in the ground
Q5: D
Q4: possibly D
Explanation:
