Answer:
Density-dependent factors are defined as the biological factors which are utilized by the population as a resource for example- food and shelter. Charles Darwin uses the concept of density-dependent factors in his Theory of Evolution to show how it affects population growth and mortality.
Charles Darwin used factors like competition, predation, and parasitism in his Theory of Evolution. He explained that habitats are limited by space and resource availability, and only the fittest organism will survive the competition.
Predator-prey relationships create density-dependent limiting factors and balance the ecosystem with limited organisms. If predators will increase in an ecosystem it will decrease the population of prey and after a certain time there will be a shortage of food as they are limited resources.
Well there are many catastrophic scenarios that we already overcome. You should consider educating yourself about the great filter. A great filter is a hypothetical barrier that each civilization can or cannot overcome. From here on things get a little complex so I won't bore you with them. But there are experts in this theory called great filter and I'm sure they can tell you a lot about.
Answer:
Villus, plural villi, in anatomy any of the small, slender, vascular projections that increase the surface area of a membrane. ... The villi of the small intestine project into the intestinal cavity, greatly increasing the surface area for food absorption and adding digestive secretions.
<span>Vaccines help develop immunity by imitating an infection. but it does cause the immune system to produce T-lymphocytes and antibodies. Sometimes, after getting a vaccine, the imitation infection can cause minor symptoms, such as fever.</span>
