Answer:
a) Teeth arose from the rough scales of ancestral sharks.
b) Skeletal developments leading to the amphibian movement onto land probably evolved from lobe-finned fishes.
d) The anterior gill arch formed the basis for the evolution of the vertebrate jaw.
Explanation:
The animals we know today have physical characteristics that are evolutionary adaptations of characteristics of their ancestors, which have undergone a series of evolutions and modifications over the years giving rise to new species that have resulted in the species we know today. This process of evolutions and adaptations also happened with the ancestral species of fish, which allowed that today, they had characteristics such as teeth and jaws. Many of these evolutions occurred even in different species, such as the evolution that allowed the amphibians to have a skeleton, which evolved from the spine fins of fish.
(A)Until the onset of PUBERTY,
Answer:
The main purpose of Negative staining is to study the morphological shape, size and arrangement of the bacteria cells that is difficult to stain. eg: Spirilla. It can also be used to stain cells that are too delicate to be heat-fixed. It is also used to prepare biological samples for electron microscopy.
Secondly, what are the limitations of simple staining? Disadvantages. It does not give much information rather than the morphological characteristics of bacteria. Through simple staining, we cannot classify a particular type of organism.
Regarding this, what is an example of a negative stain?
In a negative staining technique, an acidic, anionic dye is mixed with a cell sample. The dye changes the color of the background, not the cells, causing the cells to stand out. India ink is the classic example of a negative stain.
