An element is also a pure substance. The reason for this is because an element contains only one type of particle.
Option A is correct
Answer: unicellular organism with no nucleus
Explanation:
Answer:
Testing positive for HIV means a high chance of death and a good chance of lower reproduction rates. But some people are immune to HIV, which makes them more evolutionarily fit, likely to live longer, likely to reproduce more, which would increase the frequency of the immune allele in the population. Over time, this increase in frequency of the gene that causes immunity could spread across the human race and cause it to evolve.
