Well theory isnt proven. It means you have a strong idea about the subject your talking about. So if a scientist finds evidence that suggests something against the theory then it can be changed.
Answer: Option D " all of the above "
Explanation: DNA can be a great source of information when used as a forensic evidence. This technique has many advantages and disadvantages when used as a source of information in case of crime.
Identical twins: There are some common fragments of DNA that is same in identical twins so it can be a difficulty in deciding the criminal.
Not enough of a sample: DNA should be present in a detectable amount to be used an sample for evidence, less than this detectable amount is a waste and cannot be used as a sample for evidence.
Contaminated and degraded sample: If the sample of DNA is contaminated or degraded then the result might be incorrect and might not be used as a sample for forensic evidence.
Hence, the correct answers are all of the above.
Polio affects the central nervous system and spinal cord. It can cause muscle weakness and paralysis. Polio is a life threatening condition because it can paralyze the muscles that help you breathe.
The polio vaccine is used to help prevent these diseases in children and adults.
Every cell of the organism has the same DNA sequence and same genes. However, not all genes are expressed in every single cell at the same time. Only those genes necessary for a specialised function of a specialised cell are expressed in the specialised cell. For example, skin cells have some different proteins than nerve cells. Genes responsible for those "skin proteins" are activated in skin cells and are turned off in nerve cells.
Answer:
The correct option is option b that is<em> Homo erectus</em> is the common ancestor of<em> Homo neanderthalensis</em> and<em> Homo sapiens.</em>
Explanation:
<em>Homo erectus </em>appears about 2 mya, possibly during the Pleistocene epoch and are considered as direct ancestor of human.They are called as upright man as they use legs for walking without any support.They are thought to be capable of doing certain things like hunting, starting fire,art making, create speech etc.
<em>Homo neanderthal</em> was the most recent ancestor species of modern human as they appear about 40,000 years ago.
They became extinct as they did't fight against environmental hazards and the major cause of their extinction that scientists have claimed that they did't adapt the modern techniques that the modern human does.
