T cell activation is initiated by an activated B cell.
The B cell presents antigens on its MHC receptors. The T cell recognizes the antigen bound to the MHC. There are other cosignals that fully activate the at cells but the antigen on the MHC receptor on the B cell is where it all starts.
4.b 5.c 6.c is the right answer
es resultado de un fenómeno meteorológico que consiste en la precipitación de pequeños cristales de hielo.
Los cristales de nieve adoptan formas geométricas con características fractales y se agrupan en copos.Esta compuesta por pequeñas partículas ásperas y es un material granular.
Normalmente tiene una estructura abierta y suave, excepto cuando es comprimida por la presión externa.
La nieve es el vapor de agua que experimenta una alta deposición en la atmósfera a una temperatura menor a 0 °C y posteriormente cae sobre el suelo.
espero y te sirva
Metamorphic rocks are created by the physical or chemical alteration by heat and pressure of an existing igneous or sedimentary material into a denser form.
Answer:
Explanation:
Taigas have few native plants besides conifers. The soil of the taiga has few nutrients. It can also freeze, making it difficult for many plants to take root. The larch is one of the only deciduous trees able to survive in the freezing northern taiga.
