<u><em>Naturally acquired active immunity:</em></u> It happens when someone is exposed to a live disease and gets the disease. The person then becomes immune as a result of the first immune response.
It's sort of like a fall and learn to get up for the body.
<em><u>Artificially acquired active immunity</u></em>: It can be isert into the body by a vaccine so you won't get sick. That's why if you get a flu shot, you won't get the flu, if you get a chicken pox vaccine, you won't get the chicken pox.
It's like you're body has a personal guide telling it where and where not to step in order to not fall.
Answer:
The brain cells and skin cells both contain DNA molecules, and their DNA molecules contain the same genetic information. The brain cells and skin cells both contain DNA molecules, but their DNA molecules contain different genetic information.
Sexual Reproductions (i.e. Meiosis)
In Meiosis you have a crossing over stage in prophase I, which will result in the exchange of genetic material + the random assortment at metaphase 1 and 2 increases the variety.
There is approximately 10 billion different ways that a child can look from a mixture of the paternal and maternal genes due to all the random events that happen in meiosis/ sexual reproduction.
Your answer would be Physical weathering because it is being caused by a physical being acting upon something