B. Is the correct answer.
First, let calculate the volume of the rod shaped-bacteria:
S = length of the bacteria * surface of its side = 4.1 * (0.45 *0.45 * 3.14) = 2.6 µm3
Now, let's convert the moles into molecules (with Avogadro's law):
0.0037mol/L = 0.0037 * 6.023 *10^23 = 2.22 *10^21 molecules / L
Now let's convert The volume and the concetrnation into µm3 (molecules / µm3)
1 L = 1 dm3 = 1000 cm3 = 1000000 mm3 = 10^9 µm3
so 2.22 *10^21 molecules / L = 2.22 10^ 12 molecules / µm3
The answer is 2.22 10^ 12 molecules / µm3
<span>The stage at which all the cells show crossover chromosomes is meiotic prophase I. The crossover is the exchange of genetic material between homologous chromosomes. Homologous chromosomes are present in the meiosis I. Regarding the phase of meiosis I, it is expected that the crossover takes place in meiotic prophase I since homologous chromosomes pair up in the prophase.</span>
Ok, think about it. Does your skin prevent germs from getting inside you?
Does your skin prevent water from leaving the body too quickly? Does your skin protect your insides from getting damaged when you fall? Do you put food on your skin to absorb nutrients, or do you put food in your mouth like a normal person?