All cells I’m pretty sure
Mitral valve prolapse severe enough to cause regurgitation may directly cause INCREASE pressure in the LEFT atrium. Mitral valve prolapse is a medical condition in which the the two valve flaps of the mitral valve do not close properly, bulging upward into the left atrium. The condition may be mild or severe. Heart surgery may be required in case of the severe one.
An example of something that does not have mass would most likely be air. Because in order for something to have mass, it must take up space and have shape. Anything that you can think of that does <u>not</u> have <u>space or shape</u> does not have mass.
The answer is <span>Take consistent amounts of saliva samples from a number of people who have not eaten in 8 hours and measure the quantity of amylase in each sample.
First, the researcher needs to know the quantity of amylase in the <u>same</u> amount of saliva. Thus the amount must be consistent and not varying.
Next, people must not eat in 8 hours, so they are all in the same condition at the moment of collecting saliva. If some eat immediately before the sample collecting while some eat 8 hours before, the content of their saliva will be different.
For the correct results, all conditions must be the same.</span>
Its a surface on which an organism grows or is attached.
I hope this helps!
