Amphibians are the first tetrapod animals;
they exhibit both terrestrial and aquatic modes of lifestyle.Complete answer:
Amphibians- as the name suggests can live in both water
They are the first Vertebrates that shifted from water to land.
So, they required structural changes in them that would support their lifestyle. In their ear, tympanum appeared for better sound reception.
Tympanum is also known as tympanic membrane or ‘eardrum’ and it covers the middle ear.
We know the frogs respire with the help of lungs.
To protect the lungs better and to provide easy breathing, sternum appeared.
Sternum basically is a flat bone residing in the central region of the chest; it connects to ribs and supports formation of a complete strong ribcage.
To support the terrestrial life, eyes needed better care; hence lacrimal glands also appeared for the first time.
Lacrimal glands are paired exocrine glands. These are located on the lacrimal fossa of orbit.
The secretion of this gland is tears. Tears protect the eyes and keep them moist enough (as we know, terrestrial lifestyle is drier). So, the correct answer is ‘Tympanum, sternum and lacrimal glands’.Note:
Tympanum and tympanic bulla are different.
Tympanum is a membrane covering the middle ear and tympanic bulla or auditory bulla is a part of the temporal bone.