Problem: What is the missing first step of the following process: - The blood travels into the neophrons - Waste is expelled via the neophrons - The waste goes to the bladder in the form of urine - The clean blood exits the kidneys.

A: Blood enters the kidney

Problem: What is the missing first step of the following process: - The isotope is unstable - The isotope emits radiation - The isotope decays - The isotope loses some atomic particles - The isotope turns into a different element - The isotope is finished decaying and emitting radiation.

A: An isotope has too many protons

Problem: What is the missing first step of the following process: - The bird is nurtured by its parents - And is fed food for growth - The bird grows - Begins to learn how to fly - The bird matures - The bird leaves its nest - The bird makes its own nest.

A: A bird hatches from an egg

Problem: What is the missing first step of the following process: - Put the ice cube tray in the freezer - Wait 5 to 6 hours - Take the ice cube tray out of the freezer - Bend the tray slightly to get the ice cubes out and into a drink.

A:
Put water in an ice cube tray