A DNA molecule is shown in the diagram below.

What part of the DNA molecule is represented by the structure labeled 1?

A. an amino acid
B. a nucleotide
C. a nitrogen base
D. a phosphate

velocity and height

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.

answer; the tunica intima also called tunica interna, consists of elastic fibers,connective tissue and smooth muscle cells;

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.