Science help pls,, thank you!

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)

Each pair of clay balls represents two planetesimals. if each planetesimal is composed of the same material and is separated he the same distance, which pair experiences the frayed gravitational attraction?

Which best describes a gene? a. a sister chromatid b. a chromosome c. a tetrad d. a piece of a chromosome