Here's the answer in picture form
Answer:
The problems that can be caused by Expansion or Contraction a;long with the solutions are:
Explanation:
- The railway tracks made of steel expand during the summer and contract during the winter. This can cause them to become curved during the summer thereby causing rail derailment.In order to prevent this, an air gap is kept in between the railway lines so that they get the space to expand without getting curved.
- The electric wires linking the telegraph posts are made up of metals and so they expand in the summer and contract in the winter, which can cause them to tear. This is why the wires are loosely fixed so that they can expand and sag in the summer and contract and tighten in the winter.
- Bridges are constructed with joints where some space is maintained to allow the easy expansion and contraction in summer and winter respectively.
Answer:
Through a circumstance known as "secondary transfer DNA", or "Touch DNA".
Explanation:
Most times when a crime is committed, DNA samples are obtained from surfaces in the scene where the crime was committed. There is a very huge possibility of picking up the DNA of someone who was never at the scene of the crime and this is a result of a condition known as Touch DNA.
Because we touch several objects which can be moved to different locations and touch people who are also always mobile, our DNA cells can find their ways to a crime scene where we had never physically been to. This can lead to false verdicts of guilt.
Answer:
C. 1/4
Explanation:
Let's assume that the allele for the spotted coat is "S" and the one for the even coat is "s". The allele "L" gives short horns while the recessive allele "l" imparts long horns. The genotype of the cattle heterozygous for both traits would be SsLl. A cross between two heterozygous cattle would produce progeny in following phenotype ratio=
9 spotted coat and short horns: 3 even coat and short horns: 3 spotted coat and long horns: 1 even coat and long horns.
Therefore, the proportion of the progeny with long horns = 4/16= 1/4