What type of muscles alternate between contracting and relaxing? a) Involuntary muscles b) Antagonistic muscles c) Agonist muscles d) Isotonic muscles

Skulls of (1) modern gorilla, (2) australopithecus afarensis, (3) homo erectus, (4) homo neanderthalensis, (5) homo sapiens based on the diagram, which of the following best describes ways in which the physical appearance of h. neandertalensis and h. sapiens differ? (2 points)

Hummingbirds drink nectar from flowers, while robins eat plant seeds. what does this reduce?

What does the hardy-weinberg principle relate to? a. chances of survival of an organism b. frequency of alleles in a population c. natural selection in a species d. causes of evolution among organisms