All plant and animal groups existing together and the physical factors with which they interact compose an ecosystem<span>.</span>
Answer;
cells are very different but have similar properties
Explanation;
-Even though there are many different types of cells, they all share similar characteristics. All cells have a cell membrane, organelles organelles, cytoplasm, and DNA. All cells are surrounded by a cell membrane, all cells contain organelles, all cells contain cytoplasm and all cells contain DNA.
-Cells may differ in their number such that some organisms are made of only a single cell while other organisms are made of billions of cells
Water is in the hydrosphere
Hope this helps
Answer:
Self-antigens are not recognized and attacked by the T cells.
Explanation:
In immunology, the antigens are those substances which are bound by the antibodies. The antigens can be originated from within the bodies, known as self antigens or from outside the body, known as non-self antigens. The immune system identifies and attacks non-self invaders or the foreign harmful objects present in the body. It does not attack the self-antigens under the normal conditions. This is due to the negative selection of T cells of the thymus.