Answer:
Option D
Explanation:
In 1972, the fluid mosaic model was proposed by S. J. Singer and G. L. Nicolson to describe the structure of the plasma membrane found I living cells. The model describes the plasma membrane to possess components including phospholipid, proteins and cholesterol.
The phospholipid is arranged in two layers comprising of glycerol, two fatty acids and a phosphate group. The fatty acids which forms the tail are hydrophobic (water-fearing) while the phosphate group is water-loving (hydrophobic) giving the plasma membrane an AMPHIPATHIC nature. The other component as proposed by the model are membrane proteins and cholesterol, all responsible for the fluidity of the membrane.
The answer is to your question is A
When you swallow food, it doesn't just drop down into your stomach. Muscles contract in a wave-like motion to move the food along through the esophagus. This muscle movement is called, peristalsis, or peristaltic waves. These peristaltic waves contract behind the food bolus pushing it along the digestive tract.
Answer:
Photosynthetic organisms were making oxygen, but it reacted with the iron dissolved in seawater to form iron oxide minerals on the ocean floor, creating banded iron formations. ... The oxygen that is now in the Earth's atmosphere was not there at the beginning.
Explanation: