When does the total number of chromosomes get reduced from 46 pairs to 23 individual chromosomes?

What is thought to have caused the mass extinction at the end of the cretaceous period?

Which of the following does not describe a physical property of iron? a iron is silvery-white or gray in color. b iron has a boiling point of about 3,000°c. c iron is a magnetic element . d iron and sulfur react to form iron sulfide.

Abnormal softening of a gland is known as