Crustacea(ns) form a very large group of arthropods.
D - the theory of natural selection states that the population will be narrowed as "less fit" organisms die and "more fit" organisms survive, passing on their beneficial genes to offspring. Therefore, more organisms are born than can survive.
Answer:
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Answer:
The culture medium must be selective
Explanation:
Selective media are the media that have those ingredients which favor the growth of a particular bacterium and inhibit the growth of unwanted bacteria. So a selective media is used to selectively grow a particular micro-organism.
For example, MacConkey agar is a selective media that is used to isolate gram-negative enteric bacteria based on lactose fermenting ability. It contains ingredients like bile salt and crystal violet which inhibits the growth of gram-positive bacteria therefore it only allows the growth of gram-negative bacteria.
<em>Staphylococcus</em> <em>epidermidis</em> is a gram-positive bacteria and <em>E.coli</em> is gram-negative enteric bacteria so MacConkey agar can be used to select E.coli over <em>Staphylococcus</em> <em>epidermidis</em>. So the correct answer is the culture media must be selective.