Answer:
d. secondary endosymbiosis.
Explanation:
- When a living cell acquires another organism that eventually becomes a part of this cell, this process is known as primary endosymbiosis.
- When an organism that has already undergone primary endosymbiosis engulfs another eukaryotic organism then this process is known as secondary endosymbiosis.
- Secondary endosymbiosis has been known to occur in plastids because of which they are surrounded by two membranes. This bilayer is present because one of the layers is the original outer membrane of the organism and the other membrane is that of the organism that has been engulfed.
Tsunamis can only occur in water.
Proteins (def - organic molecules composed of very long chains of amino acids that play a crucial role in almost everything a cell does)
The plasma membrane is described as a fluid mosaic model because its made up of a phospholipid bilayer, allowing it easily to bend and move along without breaking or ripping the membrane due to the hydrophobic and hydrophilic poles of the bilayer.
