Help pls When throwing a ball, why does the triceps muscle contract?

A. The contraction of the triceps muscle causes the arm to flex.

B. The contraction of the triceps muscle causes the arm to extend.

C. When added to the force of the biceps contracting, it provides extra force to the ball.

D. The triceps muscle needs to contract in order to keep the muscle from relaxing.

Which are reasons cells undergo cell division?

Archeologists have discovered three sites showing conclusive evidence for the mastery of fire in tanzania, from a period slightly after the time that homo habilis was present in africa. these sites clearly were founded by homo erectus, the descendent species of homo habilis that migrated north, out of africa and into asia. homo erectus was known to have mastered fire, from ample evidence at sites in asia. there is no reason to attribute mastery of fire to homo ergaster, the descendent species of homo habilis that remained in africa.which of the following is an assumption on which the argument depends? (a) before their migration, homo erectus occupied african territory as far south as tanzania.(b) the strain of migration provided the selective pressure motivating homo erectus‘ mastery of fire.(c) homo ergaster would not have derived as much benefit from the mastery of fire as did homo erectus.(d) homo ergaster inherited all cultural knowledge from homo habilis, a species that did not have mastery of fire.(e) homo ergaster did not occupy regions as far south as tanzania until well after the time of these three sites.

As kate is moving down the hill, what type of energy does she have? a. sound energy b. electrical energy c. light energy d. mechanical energy