Which of the following is a testable hypothesis 

answer: - b cells

explanation: -

so, the b cells mediate their action by identifying the antigens present on the surface of the pathogens and then producing antibodies in return to mediate its effect.

the transfer for conduction is the heat transfering from the liquid to the spoon

the transfer for convection is the heat rising from the liquid to the air

the transfer for radiation is the heat going through the sides of the cup and to the air

at least that is what i would do

this age may represent the age of the earth's accretion, of core formation, or of the material from which the earth formed. this dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.