Alvin is propelled by hydraulic thrusters and features an electrical system powered by lead-acid batteries. *

Alvin is propelled by _gas or diesel___ hydraulic thrusters and features an electrical system powered by lead-acid batteries.

Explanation:

Technically, this implies that Alvin is working on motor-assist mode, using a hybrid engine.  Alvin is, therefore, propelled by an internal combustion engine (given the presence of hydraulic thrusters) in addition to an electric motor, which uses energy stored in (lead-acid) batteries.  Alvin must be a robot.

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.