Generally, it is called residual acid when the acid concentration is reduced to what percentage of the initial concentration. A: 5 B: 10 C: 15 D: 20

The mineral oil is used in Dr. Li’sexperiment to _____ A: control the concentration of odours ina slightly detectable degree. B: act as a group of comparison with thatof the other smells. C: regulate the participants’ moods bydecreasing the smell’s concentration. D: protect the participants from losingsense of smell.

The amount-of-substance concentration may be referred to as the concentration for short.

The main difference between interstitial fluid and plasma is A: The protein concentration is higher in plasma B: The Na+ concentration is higher in plasma C: The protein concentration is higher in interstitial fluid D: The Na+ concentration is higher in interstitial fluid E: The organic acid concentration is higher in plasma

Km is defined as A: Substrate concentration at maximum velocity B: Substrate concentration at half the maximum velocity C: Enzyme concentration D: Optimum temperature

The main difference between interstitial fluid and plasma is A: The protein concentration is higher in plasma B: The Na+ concentration is higher in plasma C: The protein concentration is higher in interstitial fluid D: The Na+ concentration is higher in interstitial fluid

A buffer solution must contain a relatively large concentration of acid and a similar concentration of base.

The concentration of potassium ions in the cell ( ) is the concentration outside the cell, while the concentration of sodium ions in the cell ( ) is the concentration outside the cell. A: Greater than B: Bigger than smaller than C: Less than D: Less than, greater than

He smoked with concentration. He concentrated____________ it. A: with B: on C: in D: for

A lack of sleep in the long term can reduce people’s concentration.