Answer: (A) The conclusion is valid because the independent and dependent variables in experiment were controlled.
Explanation: There are some basics requirements in order for an experiment to be valid: hypothesis, monitoring, independent and dependent variables and constants.
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:
2nd one
Explanation:
Regardless of latitude or time of year, the sun's angle reaches closest to 90 degrees (perpendicular lines are 90 degrees) -- and is therefore at its most intense -- at the midpoint of the day: noon.
Answer:
Codominance- its a relationship ebtween two versions of a gene. If both allels are domiant, it's called codominance.
Explanation:
