Avoid unecessary repetition of words or word meanings and tautology.

avoid	better
consensus of opinion	consensus
fewer in number	fewer
exact duplicate	duplicate
estimated at about	estimated
sum total	sum
whether or not	whether
in order to	to
elongated in shape	elongated
both of them	both
excised out	excised

example:

"levels of adenosine concentration increased..."

is better as:

"adenosine levels increased..."