I am pretty sure it is CD4 cell
Physical property is the characteristic that can be observed, using the five sense, without changing or trying to change the composition of the substance. Chemical property on the other hand is a characteristic of how the substance reacts. It can not be observed without changing the substance into something else. A physical change is a change in which the form or appearance of matter changes, but not its composition.
Answer:
Through natural selection the disease gain immunity to the antibiotic.
Explanation:
As the antibiotic kills off the members of the population that are not resistant, leaving only the resistant members. These members then reproduce, passing the immunity to their offspring, causing the population to become immune.
Answer:
One Idea was the appreciation that the age of the Earth was much greater than had hitherto for been imagined.
