PCR (polymerase chain reaction) is a relatively new advance (1980's) but it has a great impact in our lives. Specifically, in forensic science, PCR is useful in many sorts of crimes . Up until the PCR method, in order to identify a person forensic scientists would use fingerprints or some other ambiguous methods like teeth marks etc. But now, with PCR, we can compare the genetic material found on a crime scene and compare it with a suspect's genetic material, definitively concluding whether they are the same person or not. The way this works is that we collect a sample from the crime scene with DNA and then PCR amplifies the quantity of DNA in that sample. One of the apparent advantages of this method is that PCR works with even a very small sample, often not even a single cell is required. This makes crime scenes full of information. Hence, succinctly, PCR has helped modern forensic science in that:
1) its results are more definitve than traditional identification methods and subject to less ambiguity
2) it is relatively fast
3) new pieces of evidence can be of value (like some hair cells) and identify the crominal in cases that in older times would be impossible to solve.
Answer:
A. The variation resulting from meiosis and the union of gametes means some individuals will have a chance of colonizing diverse distant environments successfully.
D. Vegetative propagation is more efficient than sexual reproduction when the current generation is well adapted to the local environment.
Answer:
There are many receptors for thyroxine on different target cells (tissues), so its effect can be huge
Explanation:
Target cell for a certain hormone is a cell that have hormone receptor specific for that hormone. There are two main types of receptors on target cell:
- cell membrane receptors (also called trans membrane receptors)-usually for peptide hormones, such as insulin
- intracellular receptors (also called nuclear receptors)-usually for steroid hormones, such as testosterone.
Hormone binding to the receptor leads to the signal cascade within the cell, which results in cell response.
Receptors for thyroid hormones are nuclear receptors.
Answer:
Crossing over
Explanation:
Please see the attachment
Answer:The world population increased from 1 billion in 1800 to 7.7 billion today. The world population growth rate declined from 2.2% per year 50 years ago to 1.05% per year. Other relevant research: ... We show how the world population grew over the last several thousand years and we explain what has been driving this change.
Explanation: BRAINLY Sometimes don't give u the right answer....SO TRUST ME ON THIS ONE <3 u should get a A++++
