Answer:
Hershey and Chase demonstrated that genetic material is contained in the DNA molecule. By using bacteriophages they observed that DNA, but not proteins, contains the genetic material. These researchers tagged DNA with radioactive phosphorus and then separated bacteria and protein phages by centrifugation, observing that bacterial pellet was radioactive
Answer – B (Electrons)
When atoms combine, their nucleons fuse to produce a new nucleus and interactions occur between their electrons, particularly the outer valence electrons. The interaction between the outer valence electrons of the combining atoms forms bonds between them.
Answer:
They help to stop harmful germs from entering the body
Explanation:
- The skin can prevent bacteria and microorganisms from entering the body (unless it is damaged)
- Mucous membranes line the mouth and nose and are coated with secretions that fight microorganisms and harmful bacteria
- Tears help to clear debris from the eye to prevent infection
Answer is b. Burning fossil fuels causes a decrease in the pH of ocean water making it more acidic.
Burning of fossil fuels release carbon dioxide and other harmful gases in the atmosphere. Carbon dioxide gets dissolves in the ocean to form carbonic acid. Due to formation carbonic acid, the pH of ocean water changes slightly. The average pH of ocean water was 8.2 slightly basic. Now it 8.1, it means there is 25 % increase in acidity of ocean water.
Answer: Antibiotic Resistant Mutation
Explanation: Not all of the bacteria die because there are individuals in the population that have an antibiotic resistant mutation, which causes them to be adapted to dealing with the antibiotic. There will be a large population of bacteria again because the ones with the mutation survive, reproduce, and pass the antibiotic resistance trait on.
