The pectoral girdle articulates with the axial skeleton only at the Sternoclavicular ligament<span>. The pectoral girdle connects the upper limbs to the axial skeleton and serves as the attachment site for the muscles of the upper back, chest and neck. The clavicle is the only long bone that lies in a horizontal position in the body. it has three regions; the medial end, the lateral end, and the shaft. The medial end has a triangular shape and articulates with the manubrium portion of the sternum. This forms sternoclavicular joint, which is the only bony articulation between the pectoral girdle of the upper limb and the axial skeleton. </span>
All,organisms are made up of one or more cells. The cell is the basic unit of all organisms. All cells come from existing cells. The scientific theory of cells is what scientists believe are true about cells.
I believe it is D bcuz there is no more reproducing of that species so it will eventually die out.
The right answer is B.
Nitrogen fixation is done by decomposers that are prokaryotes (bacteria).
<u>Take the example of legumes.
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The different species of rhizobia bacteria, which are able to infect the roots of legumes (Fabaceae family), are specific to certain host plants. Rhizobium phaseoli infects beans (Phaseolus sp).
Bacteria cause the formation of nodules on the roots by penetrating the root hairs, and transform into larger "bacteroids". The nodules are the seat of a symbiotic activity in which the plant provides the sugars and energy from photosynthesis, and in return benefits from the amino acids that are produced there.
Answer:
b). activation of T cells
Explanation:
An APC (antigen-presenting cell) can be described as an immune cell, which detects, uptakes, and informs the acquired immune response when an infection takes place. B cells, macrophages, and dendritic cells are antigen-presenting cells.
These cells play an important role in activation of T cells. T cells are unable to recognize soluble or free antigens and can only recognize antigens processed and presented by carrier molecules, such as MHC molecules.
Presence of MHCII molecules is a defining feature of APCs that process and present antigens to T cells. Hence, all antigen-presenting cells help in activation of T cells.
Thus, the correct answer is option (b).
