Answer:
The environment usually refers to all the biotic and the abiotic components that are surrounding us. This environment undergoes changes depending upon various factors which can be natural and/or due to the anthropogenic activities.
When there occur rapid environmental changes, then it directly affects the lives of species, in different ways, such as-
- Those species that are comparatively weaker in adapting according to the environmental changes that occur, will not be able to cope up with the new environment. They may become extinct.
- Some variety of species will be able to adapt to the new environment because of their easily adapting capabilities.
- The traits that will be developed within the species in the new environment will be more successful in terms of reproduction.
- The previously existed traits may have a harmful impact in the newly formed environment.
The thymus gland is the main organ of the lymphatic system. Located in the upper chest region, the primary function of this gland<span> is to promote the development of specific cells of the immune system called T lymphocytes.</span>
The best example that illustrates a sensitive period is
letter b, where the child tries to learn in speaking a second language because
this is considered to be a sensitive period in which is the period for a
development of new opportunities that a child could learn in which learning to
speak a second language is considered to be a sensitive period.
T cells
The immune response to a transplanted organ consists of both cellular (lymphocyte mediated) and humoral (antibody mediated) mechanisms. Although other cell types are also involved, the T cells are central in the rejection of grafts. The rejection reaction consists of the sensitization stage and the effector stage.
