The correct answer is none of the above.
Bacterial cells can transfer genetic material through a process called bacterial conjugation. This process involves the direct physical contact of the bacterial cells and a horizontal gene transfer. The genes which are transferred are most of the times beneficial for the recipient, such as genes for antibiotic resistance.
In this example, bacterial cells cannot have physical contact, since they are separated by a glass filter. Therefore, the bacterial conjugation cannot happen. Given that no gene transfer can be achieved, the AY strain remains bio- trp- and is unable to grow on any medium that lacks bio or/and trp.
Answer:
atomic number is 4 and neutron is 12
Answer:
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Answer : A metal in group 16 of the periodic table can become a chemically stable ion by gaining 2 electrons.
Explanation :
The group 16 element are oxygen, sulfur, selenium, tellurium and polonium.
The general electronic configuration of group 16 elements is, 
As we now that there are total 6 electrons in p sub-shell. So, a metal in group 16 can become a chemically stable ion by gaining 2 electrons.

Hence, a metal in group 16 of the periodic table can become a chemically stable ion by gaining 2 electrons.