Question

An egg of bird was coated with varnish and then incubated. The egg did not hatch because the developing embryo

• A. Could not excrete and died
• B. Could not utilize yolk in the pressure of excess amount of nitrogenous wastes
• C. Died because of depleted $O_2$ supply
• D. Died because of toxic effect of varnish

Answer 1

The correct option is C Died because of depleted $O_2$ supply

The egg of birds and reptiles is rich in yolk and supports full development of embryo. They lay eggs and are called oviparous animals. The eggs are however surrounded by a porous calcium rich shell. The fertilisation is internal, while the egg is still present inside the female animal. Once the egg is laid it conducts gaseous exchange with the environment. If it is coated with varnish or paint or oil the gaseous exchange is hampered and embryo cannot develop.