Question

why do populations encounter more competition and disease as their population increases? due to the absence of limiting factors because of increased disease immunity higher population density optimal environmental conditions

Explanation:

When population density increases, there is more competition for limited resources (such as food, water, and space). Also, higher population density makes it easier for diseases to spread (more hosts in close proximity for pathogens to infect). Limiting factors would prevent population growth, so their absence doesn't explain increased competition and disease when population is already high. Increased disease immunity would reduce disease impact. Optimal environmental conditions might support population growth but don't directly explain more competition and disease.

Answer:

higher population density