Species belonging to different time periods are

Association of animals belonging to different species, where both partners are benefited, is called:

Association of animals belonging to different species where both partners are benefitted, is called

Elements belonging to the same period have

Elements belonging to the same period have-

Why does the size of Hafnium and Zirconium is same although they belong to different periods of same group ?

All the elements belonging to second period are:

The overall species diversity among different communities belonging to different ecosystems within a large geographic area is called-

When species mate at different times of the day of year there exist

The sexual reproduction that occurs among two genotypically different organisms belonging to the same species, is called _______.