Out of the following give choices;
a. All DNA strands
contained only the heavy nitrogen isotope.
b. Half of the DNA strands contained only the light nitrogen
isotope.
c. All DNA strands contained both heavy and light nitrogen
isotopes.
d. All DNA strands contained only the lighter nitrogen
isotope.
The answer is b. Meselson–Stahl experiment demonstrated the semi-conservative model of DNA replication.
When DNA is replicated, one strand of the new double
helix strand is the parent's strand while the other is the newly synthesized
one. This made the semiconservative model stand out over the other two, dispersive
and conservative models.
Answer:
The sex chromosomes are referred to as X and Y, and their combination determines a person's sex. Typically, human females have two X chromosomes while males possess an XY pairing. This XY sex-determination system is found in most mammals as well as some reptiles and plants.
Men determine the sex of a baby depending on whether their sperm is carrying an X or Y chromosome. An X chromosome combines with the mother's X chromosome to make a baby girl (XX) and a Y chromosome will combine with the mother's to make a boy.
Explanation:
Animal cells each have a centrosome and lysosomes, whereas plant cells do not. Plant cells have a cell wall, chloroplasts and other specialized plastids, and a large central vacuole, whereas animal cells do not.
Answer:
Both players on the serving doubles team have the opportunity to serve and score points until they commit a fault *(except for the first service sequence of each new game).
The first serve of each side-out is made from the right-hand court.
If a point is scored, the server switches sides and the server initiates the next serve from the left-hand court.
As subsequent points are scored, the server continues switching back and forth until a fault is committed and the first server loses the serve.
When the first server loses the serve the partner then serves from their correct side of the court (except for the first service sequence of the game*).
The second server continues serving until his team commits a fault and loses the serve to the opposing team.
Once the service goes to the opposition (at side out), the first serve is from the right-hand court and both players on that team have the opportunity to serve and score points until their team commits two faults.
In singles the server serves from the right-hand court when his or her score is even and from the left when the score is odd.
Explanation:
