The answer is stem cells, they consist of classes of cells
that are undifferentiated and are able to be classified them into types like
specialized cells. They consist of having two main sources that will help them
develop and mature, these main sources are called the embryonic stem cell and
the adult stem cell.
The right choice would be A
Answer:
Valley lizard = Oviparous
Mountain lizard = Viviparous
Explanation:
In Darwin's theory survival of the fittest, he believed species adapt or change within their environment. So I believe lizards living in a valley would be more safe to lay their eggs but lizards living in the mountains would be viviparous because of the non-predicted and unsafe environment which could harm the better chances of development of the offspring.
Meiosis occurs in a series of different phases and creates genetically unique reproductive cells. The process which helps make meiotic cells genetically different and occurs during prophase I, but not during prophase II, is crossing over (C). Crossing over is the exchange of genetic material between two homogenous chromosomes. It is one of the final phases of prophase I. This process is called synapsis. It occurs when the matching regions on the matching chromosomes break and then reconnect to the other chromosome
The main difference between a plant cell and the animal cell is the presence of cell wall.
In the plant cell, the cell wall is present, but in the animal cell, the cell wall is absent.
Hence, in the onion cells, the cell wall around the cell would be clearly visible, whereas in the case of cheek cell, the cell would only be lined by a cell membrane, a cell wall would not be present.
Further, the plant cell would have the chloroplast, as they perform photosynthesis, but the animal cell would not have chloroplast. Unlike animal cell, the central vacuole in the plant cell is bigger and clearly visible.
