Answer:
Alfred Hershey and Martha Chase
Explanation:
In 1952 Alfred Hershey and Martha Chase were working with bacteriophages or phages, which are viruses that infect bacteria. They knew that a phage had an outer shell of protein and an inner core of DNA. In addition, from the electron microscope observations, they also knew that during infection the virus attacks the bacterium by its tails and introduces its genetic material into the bacterium to multiply using its metabolic machinery. They radioactively labeled two sets of phages: one with 32P (which marks only DNA) and another with 35S (which marks only proteins). In two parallel experiments, they infected bacteria with viruses marked on their DNA and with viruses marked on their proteins. The cultures were shaken with a mixer to separate the virus particles from the bacterial coatings. They then performed a centrifugation to separate the phages from the bacteria, so that the larger and heavier bacteria remain in the pellet, while the phages remain in the supernatant. They found that the radioactivity of 35S appeared in the supernatant while that of 32P appeared in the sediment, from which new radioactively labeled virus particles appeared, demonstrating that DNA was the genetic material.
Answer:
relaxation
Explanation:
relaxation is best relax to muscle. it is relax our bones and muscles.
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Giving care to a patient who is bleeding without wearing protective barriers such as disposable gloves could be dangerous because it can expose an individual to infections. The best way for you to care for this person is;
1. to have him/her to hold or apply pressure on the wound on his forehead.
2. Cover the cuts on the forehead with a bandage and ensure immediate washing of hands after providing care for the person.
Answer:
The correct option is C.
Explanation:
There are three modes of heat conduction, these are conduction, convection and radiation. Heat transfer by conduction usually involves the movement of heat through solid substances. For instance, in the scenario given in this question, the warm surface is the solid substance through which heat is passed to the insects' bodies. Thus, conduction requires direct contact.
Heat transfer by convection method usually involves the movement of heat through liquids or gases while radiation can occur in vacuum.
