Explanation

300 grams is the weight of the heart of an adult human being.

The average gross weight of the heart was  for men 289.6 g

The average gross weight of the heart was  for women 284.7 

At the age of 61-70 years, the average weight of men was 345.9

At the age of 61-70 years, the average weight of women was 285.1

*****ٓAdditional Informations*****

A human brain weight is 1400 grams.