The elasticity of the arterial walls allows the blood pressure to change suddenly as a result of physical exertion.
The elasticity of the arterial walls allows for sudden changes in blood pressure that can result from physical exertion.
The elasticity of the arterial walls allows the blood pressure to change suddenly as a result of physical exertion.
The elasticity of the arterial walls allows for sudden changes in blood pressure that can result from physical exertion.
The idiom "allow for" denotes the way the design of something can accommodate a difficult or challenging factor. Changing the blood pressure is not the job of the arterial wall, so these walls don't "allow them "to" change. Instead, the blood pressure changes for other reasons, and the arterial wall must respond to this change. For this, we need the "allow for" idiom.