A piece of aluminum has a mass of 109 grams and a volume of 20 cm3. What is the density of the aluminum?

2180 g/cm3

5.45 g/cm3

4.55 g/cm3

0.183 g/cm3

List two limitations of natural selection

Cell specialization occurs by the process ofa. reproductionb. differentiationc. maturationd. growth

Identify the type of energy used in each action. the flexing of an arm muscle: a signal transduction process by a neuron: a ball at the top of a hill: 1. electrical energy 2. mechanical energy 3. gravitational potential energy