<span>Essential part of the maculae involved in static equilibrium is otoliths. The otolith organs sense gravity and linear acceleration such as from due to initiation of movement in a straight line. Persons or animals without otolith organs are imbalanced. The otolithic organs sense motion according to their orientation.</span>
Answer:
D
Explanation:
Cancer cells exhibit uncontrolled and disorganized growth. Formation of new blood vessels is required to bring nutrients and oxygen to cancerous tumors. Cancer cells cannot enter the cell cycle and therefore are mortal. cancer cells enter the cell cycle repeatedly, and in this way they are immortal.
Answer:
The animals present body structure is due to evolution. It is seen in each part including the structure of the heart. The vertebrate heart becomes complex from a simpler form.
Invertebrates, the heart of fishes is two-chambered having one auricle and one ventricle. The deoxygenated blood gets purified in the gills. They are aquatic and no lungs for breathing. The hearts pump a mixture of oxygenated and deoxygenated blood to the body.
The amphibians and reptiles have 3 chambered heart as they lead terrestrial mode of life. The gills modified into the lungs. The left auricle receives pure blood and the right auricle receives deoxygenated blood. The blood purified in the lungs and in the ventricle, both types of blood get a mix. The ventricle pumps the mixed-blood throughout the body.
In the case of birds and mammal, the heart is 4 chambered and the oxygenated and deoxygenated blood are separated. These two are higher vertebrates. No mix of pure and impure blood, the body receives only the oxygenated blood.
This shows to construct the phylogenetic tree of vertebrates - the fishes should be in the bottom, and above it amphibians, reptiles, then, mammals and birds on the top branch of the tree. As the chambers and structure of the hearts modified one after another.
