Which of the following is true about enzymes?

i. enzymes typically catalyze reactions at much higher rates than chemical catalysts.
ii. enzymes are often very specific for their substrates.
iii. enzyme activities can often be regulated.
iv. enzymes typically act under milder conditions of temperature and ph than chemical catalysts.

All options are correct.

Explanation:

All options are correct.

Enzymes being faster, than chemical catalysts and their reaction rate is almost 10 times faster.They are highly specific producing large amount of good residues and can work at mild conditions, physiological pH and temperature.

They can be regulated by other molecules that either increase or reduce their activity.

Molecules that increase the activity of an enzyme are called activators, while molecules that decrease the activity of an enzyme are called inhibitors.

1.solid

2.carbon dioxide

3.helium

thats a little if u want the answer just look it up on google thats what i do haha : )