2.When is a differential medium also a selective medium and vice versa?

Answer 1

A selective medium "selects" for a certain trait allowing bacteria to grow. For example, Mannitol Salt Agar (MSA) is a medium that "selects" for the growth of halotolerant bacteria. It contains 7.5% NaCl, giving the medium a high salinity. Thus only bacteria that can grow in a high level of salinity can grow and survive in this environment. An example of this would be Staphylococcus aureus.

A differential medium is one that distinguishes between defining characteristics of organisms. Mannitol Salt Agar is a selective AND differential medium. Once you know that a bacteria, in this case, S. aureus, can grow on MSA, you look to see if it ferments mannitol. (This is indicated by a yellow halo...when mannitol is fermented, the pH of the medium drops, then turns the pH indicator yellow.) Thus it differentiates between mannitol fermenters and non-mannitol fermenters.

Different media can select for many things, like Gram-positive bacterial growth (thus inhibiting growth of Gram-negative organisms), or vice versa, and can differentiate between a variety of characteristics.

Answer 2

It's a bit of both, the media know that her story sells well, and Jade is taking full advantage of this so she can ensure that her sons can have a better future. At the same time she's raising awareness for cervical cancer. If this is her wish then so be it, she's not forcing people to watch her and it's helping her take her mind off her pain. I just wish her the best and hope her wedding goes well on Sunday, she's very brave.

Answer 3

selective media is used to differentiate between bacteria as only one type grow
while differential contain indicator for bacteria as PH indicator which give certain colour with different bacteria