The right option is; dark-field microscope
A light microscope that makes the specimen appear light on a dark background is called a dark field microscope.
Dark field microscopes are light microscopes that are used in different ways to clearly view various specimens that are unstained, transparent, and hard to see using a light field unit. Dark field microscopes are very effective because they show the details of unstained and live samples. It is also very simple to use, and inexpensive to set up.
Data on one variable can be displayed in <span>histogram.</span>
The ultimate source of energy is sunlight, and living things must break the sunlight down using their own methods to use it.
One is probably because your friend has a stronger immune system than you and is able t fight the bacteria infection. The other is probably that your friend is also infected but does not show any symptoms of the infection, in what is referred to as latent infection. The bacteria enters a lysogenic cycle in your friend’s body rather than the more virulent lytic cycle (that happens to you).