Question

Which of these describe(s) variation within a species or population? A population is defined as members of the same species living together in the same area and who are likely to breed with each other.
A) Hummingbirds have beaks able to collect nectar from flowers while woodpeckers have beaks able to collect insects from tree bark

B) Polar bears have differences in the number of hairs per square inch of their skin

C) Evergreen trees have needle-like leaves

D) Fish use gills to obtain oxygen from water

Answer 1

Answer:B. Polar bears have variable hair density

Explanation: humming birds and woodpeckers are in different genera. Evergreen trees: the question should actually refer to conifer genera and angiosperm genera such as Casuarina and Exocarpos since many evergreen trees do not have needle like leaves, but in any case this again involves different species from many genera. Gills are a plesiomorphy common to all fish. Polar bears (Ursus maritimus) is a single species and hair density is within-species variation.