External skeleton is the correct answer. Hope this helps out !
Answer:
Vacuole. A vacuole is a membrane-bound cell organelle. In animal cells, vacuoles are generally small and help sequester waste products. In plant cells, vacuoles help maintain water balance.
Explanation:
These dark areas are called maria. They are thought to be formed by volcanic eruptions in the moon's history.hope this helped:)
The correct answer is that "the T cell enters a state of anergy".
The activation of T cells requires two signals: (1) antigen specific signal presented by an antigen presenting cell (either a macrophage or a dendritic cell) that activates t cell receptors and (2) co-stimulatory signals that is not antigen specific but rather found in the plasma membrane of the antigen presenting cell (i.e. CD28). In the absence of a co-stimulatory signal, the t cell will enter a state of anergy or the inability to produce an immune response toward an offending antigen.
Mature and established trees die for a combination of reasons but sudden browning of foliage is typically associated with a lack of water supply to the canopy. Water supply can be cut off to the canopy due to obvious issues including deficiency or root damage.
<h3>What is Carbon?</h3>
- Carbon is a chemical component with the symbol C and atomic number It is nonmetallic and tetravalent—its atom makes four electrons unrestricted to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon produces up only about 0.025 percent of Earth's crust.
- Carbon is employed in some way in almost every industry around the globe. It is used for fuel in the form of coal, methane gas, and crude oil (which is used to produce gasoline). It is used to make all sorts of fabrics including plastics and alloys such as steel (a mixture of carbon and iron).
- Carbon is a chemical element with the symbol C and atomic number 6. Categorized as a nonmetal, Carbon is a solid at room temperature.
To learn more about Carbon, refer to:
brainly.com/question/1601509
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