Autotrophs are organisms that can make their own food for the biosphere.
This term comes from the Greek terms:
Auto- meaning "self" and Troph- meaning "feeding or growth"
So autotroph quite literally means "to feed oneself". Autotrophs, for the most part, use photosynthesis from sunlight to produce their own sugars.
Plants are the primary autotrophs on Earth!
When there is heavy competition between two species these results may surface. First, even if there is just a little advantage of one species, the tendency is the best competitors will dominate the other. This may lead to the extinction of the weaker species. Another result is, competition may cause the traits of the competing species to evolve. This result is called character displacement. This is what happens when for instance the species live in the same area and have the same and common niche; the characteristics of the species evolve in order for them to minimize niche overlap. This is also for them not to have competitive exclusion. To add to that, when there is heavy competition, the finite resources will not be enough for all competitors who have all access to the resources. This may lead to very low survival rates.
No. The T-cell has surface receptors made of proteins that are COMPLEMENTARY to only ONE SPECIFIC antigen due to the specific sequence of amino acids resulting in a specific tertiary structure of the protein. Thus, the T cell will only recognise the antigen it’s receptors are complementary to.