Angiosperms are known as flowering plants. Gymnosperms are seed producing plants like trees that don’t have flowers, so that leads you to ferns and horsetails. Ferns have spores on them that they use to reproduce with and they don’t have flowers . -isboggio
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.
A. Carbon Dioxide and Water
