The upper arm bone is the

a : radius
b : ulna
c : clavicle
d : humerus

Draw the structure of dna nucleotide with adenine as nitrogenous base

Most animal cells membranes have proteins that pump ions out of the cell and potassium ions into the cell

Which of the following happened during the precambrian era? the first prokaryotic cells the first eukaryotic cells development of photosynthesis all of the above