Question

Which two characters out of (a)-(e) given below are common to dogs, humans, squirrels, bats, camels, and monkeys?
A. Scales on the skin
B. Wings
C. External ears
D. Give birth to young ones
E. A functional tail

Answer 1

Every species is represented by its inherent characteristics. The characteristics can be genotypic and phenotypic. The genotypic characteristics are hard to compare. They need testing and analysis. But phenotypic characters are visible features. Organisms can be differentiated and compared based on physical characters. Scales on the skin, wings, external ears, giving birth to young ones, a functional, etc are phenotypic characteristics.

Complete answer: To understand which of the given phenotypic characters belongs to which organism and which organisms share the same characters, let us discuss each character individually.
-Scales on the skin are characteristic of most reptiles. But in humans and some other animals, the scaling of the skin refers to a disease of the skin. It is representative of the shedding of skin. Mostly the scales appear when skin dries up or due to some infection. None of the given animals have scales on the skin.
-Wings are the modifications of the forelimbs that are seen in birds majorly. The bat possesses a pair of wings. These are sharp and delicately structured wings different from that feathery wings of birds. No wings are seen in dogs, humans, squirrels, camels, and monkeys.
-External ears refer to the outermost segment of the ear. It consists of the auditory canal and auricle that helps in the sound collection. These are evident in all of the given animal species.

-Giving birth to young ones is a characteristic property of mammals and primates. Animals that reproduce by giving birth to off-springs without egg or shells are called viviparous. All of the above-given animals are viviparous.
-A functional tale is seen in dogs, squirrels, camels, and monkeys. Tails are developed to serve various functions including locomotion in fishes, sense of balance in cats, brushing off insects, in dogs, holding branches in monkeys, etc. There is no tail present in humans.
Therefore, options c and d are correct.

Note: Characteristic features are modifications or some special organs present in species that differentiates one from the other. Some similar characters appear in organisms as a result of convergent evolution. This means that organisms inhabit different geographical locations, but habitat factors are the same that leads to the development of similar characters.