What is the missing first step of the following process: - Two types of proteins exist in filaments in the muscles - The filaments move when the brain instructs them to - The motion of the filaments cause the muscle to shorten and contract - Opposing pairs of muscles exist in order to provide the necessary range of motion.
Ans: Electrical signals in the brain travel through nerves to muscles

What is the missing first step of the following process: - Animals gain weight - The season changes to one with bad (cold, snowy) weather - Animals find a place to hibernate - Animals enter a type of 'sleep' (hibernation) - Body processes slow down - The animal's heart rate and breathing rate slow - The animal loses weight more slowly than usual - The animal is able to survive not eating or drinking without hurting itself -
Ans: Animals eat a lot during good (warm, clear) weather

What is the missing first step of the following process: - The shaft of the turbine spins - Shaft is connected to a generator - The generator uses the spins of the shaft to rotate a rotor - The rotor spins inside the core, which has magnets inside surrounded by wire loops inside - The spinning of the rotor in the core generates electricity -
Ans: Wind passes the turbines and moves the blades

What is the missing first step of the following process: - Water is in the air - The water forms tiny ice crystals - The ice crystals collide with each other - The ice crystals stick to each other - The ice crystals get bigger as more of them stick together - The ice crystals get too heavy to be in the air - The ice crystals become snowflakes - The snow flakes fall to the ground as snow.
Ans: The air is cold