Answer: Because they have built up immunity from past medications.
Explanation: As people get sick and are given antibiotics the 99.9 % are removed but that one percent from the bacteria is able to overcome the antibiotics and make itself stronger and immune to the medicines, then the bacteria evolves and a new person will get infected and will need stronger antibiotics further more the cycle is repeated.
Vestigial structures<span> are often homologous to </span>structures<span> that are functioning normally in other species</span>
Oranelles carry out specific functions within the cell
The tRNA molecule determines the type of amino acid!
It is known as a concentration gradient which in diffusion will always flow from ares of high concentration to areas of low concentrations
So i believe the answer to this is A.
