<span>Stem cells. There are two types of stem cells: adult stem cells - these are unspecialised cells that can develop into many (but not all) types of cells. Embryonic stem cells - these are unspecialised cells that can develop into any type of cell. And that's all! ;)
Hope this is useful !!!^_~!!!</span>
Answer: Question 1 answer: Skin cells continually replicate
Explanation: The cells in the superficial or upper layers of skin, known as the epidermis, are constantly replacing themselves. This process of renewal is basically exfoliation (shedding) of the epidermis. But the deeper layers of skin, called the dermis, do not go through this cellular turnover and so do not replace themselves.
Question 2 answer: Heart cells undergo terminal differentiation
Explanation: Different cell types (e.g., neurons, skeletal and heart myocytes, adipocytes, keratinocytes) undergo terminal differentiation, in which acquisition of specialized functions entails definitive withdrawal from the cell cycle.
Question 3 answer: DNA replicates in the nucleus
Explanation: DNA replication occurs in the cytoplasm of prokaryotes and in the nucleus of eukaryotes. Regardless of where DNA replication occurs, the basic process is the same. The structure of DNA lends itself easily to DNA replication.
Question 4 answer: The ability to reverse terminal differentiation might affect gene expression in a complex organism
Question 5 answer Cytoplasm replicates during mitosis
Explanation: This process involves replication of the cell's chromosomes, segregation of the copied DNA, and splitting of the parent cell's cytoplasm. ... The outcome of binary fission is two new cells that are identical to the original cell.
Answer:
The correct answer is b. must be present in a population before natural selection can act upon the population
Explanation:
Genetic variation can be caused by mutation, recombination between chromosomes during meiosis and by fusion of two genetically different gametes during sexual reproduction.
This genetic variation is necessary for the evolution of any population. Natural selection acts on every individual and it decreases the frequency of those alleles that are not suited for the environment and increase the frequency of those alleles which helps the individual to survive in the changing environment.
Therefore genetic variation must be present in the population before natural selection act on the.
Hi you are cute thank you
