Although having evolved independently, the tracheal tubes of mammals and insects are both supported by rigid tissues. the trachea of a mammal is supported by cartilage, and the tracheae of an insect are supported by chitin. what selective pressure most likely led to the convergent evolution of these respiratory structures?

The answer is B.  Which is “When the air is in the respiratory medium, there is a greater risk that the tracheal tubes will collapse. The cartilage in the respiratory system gives support to the tubes against negative or positive pressure, during respiration, hence keep it open.  

cancer   is   essentially   uncontrolled   mitosis   of specialized cells

ans.

gregor john mendel is known for study of inheritance in pea plants. he used garden pea plant for his study, having alternative traits for various characters. he performed cross-breeding in pea plants to check how characters are transmitted between parents to offspring, such as cross between pure tall and pure dwarf plant. mendel studied the inheritance patterns in pea plants for various generations.

thus, the correct answer includes options and f).