Questions

Isotopes are atoms of the same element that have different mass numbers.

Example : Hydrogen, Deutirium and tritium all these have different mass but same atomic numbers.

The building blocks of the nucleic acids are "Nucleotides".

Each nucleotide are composed of three parts. They are ::

1.Pentose sugar

2.Nitrogenous bases

3.Phosphoric acid.

The mammalian heartis called myogenic (myo = muscle, genie = originating from). It means the heart beat or the activities of the heart are auto regulated which originates from a muscle called nodal tissue.In the human heart,heartbeat originates and contraction is initiated by a special modified heart muscle known as sinoatrial node. It is located in the right atrium; while the QRS waves are the depolarisation of the ventricles, which initiates the ventricular contraction.The T-wave represents the repolarisation,that is, the return of the ventricles from excited tonormal state.Hepatic portal system is the unique vascular connection that exists between the digestive tract and liver. This vein carries blood from intestine to the liver.

Gregarious is spelt correctly which means sociable.

Plants developing in dry conditions are called as xerophytes.