The eardrum is a thin flap of skin that is stretched tight like a drum and vibrates when sound hits it.
The three mechanisms which regulate the heart are endocrine, cardiovascular and Sinoatrial nodes.
The endocrine system consists of the glands and hormones of the human body. The cardiovascular system is the organ system which is responsible for the circulation of the blood around the body and the oxygenation of the body's tissues. The sinoatrial node (SA node) generates the electrical impulses and is considered the natural pacemaker of the heart.
Answer;
Endosymbiotic theory is important as it explains the origin of the chroloplast and mitochondria. It also explains the formation of the eukaryotic cells.
Explanation;
Endosymbiotic theory explains the origins of eukaryotic cell organelles such as mitochondria in animals and fungi and chloroplasts in plants.
Mitochondria and chloroplasts are believed to have developed from symbiotic bacteria, specifically alpha-proteobacteria and cyanobacteria, respectively.
C. They provide instructions for protein synthesis and determine traits.
