Answer:
To communicate with each other
Explanation:
Cows use sound (mooing) to communicate with each other and their environment. Cows are herd animals and have complex social structures. Mooing is one way that they interact and how they express their emotions
Answer:
Bring to the boil. Carefully place the can in the saucepan, ensuring there's enough water to completely cover the can at all times, topping up water frequently throughout the cooking process. Simmer, uncovered for 3 hours.
Answer:
Elaina's scientific investigation is missing controlled variables.
Explanation:
A good scientific investigation should vary only the factor that is studied (the speed of the music. All other factors should be kept constant.
She hasn’t controlled for <em>volume</em>. The volume of the music may affect the rate at which the listener’s heart rate will increase. She should have measured each person’s pulse after the same period of listening.
She hasn’t controlled for <em>age</em>. A grandmother may respond to loud music differently from a teenager. All her subjects should be about the same age.
She hasn’t controlled for <em>wakefulness</em>. A person may respond to music differently when awake than when asleep.
For H2O(l) at 100 ∘C, d=0.958gcm−3 and ΔvapH=40.7kJmol−1.
