Answer: DNA
Explanation:
A chromosome is a thread-like material with a long structure found in the cell nucleus. It mainly contains DNA and proteins. Due to the presence of DNA in chromosomes, it carries several genes.
The total number of chromosomes in human cell is 46: 44 are non-sex chromosomes while 2 are sex chromosomes
The term that refers to all areas of Earth where all life exists is call the Biosphere
Barking when frightened
Explanation
The others require you to teach the dog how to do it but I dog doesn’t need teaching to bark it comes naturally
Alligators,crocodiles,caimans and lizards