1. Calling for attention could mean asking for a mate, or simply marking territory.
2. The rattlesnake's rattle serves as a warning to all its prey and predators.
3. A sweet scent for a plant attracts insects to pollinate their flowers.
4. Some may have a unique way of calling out, or weird movements. Take tropical birds for example.
5. I think it's because that the females are attracted to a certain call or movement.
6. communication is talking to each other.
7. Stimuli can induce the hypothalamus in an organism's brain to react accordingly.
8. Animals need a voice, or a call, or a maovement, or anything to get their point across.
That was a lot of typing, but i'm done. :)
Ice is a solid. Water is a liquid. Water vapor is a gas.
B. It is open to change as new evidence or data is discovered. If scientists discover new evidence, they must modify their theories to conform with the new data.
A. is <em>incorrect</em>. Scientific laws are so well established that there can be no exceptions.
C. is <em>incorrect</em>. A scientific theory is the collective judgement of scientists as to the best explanation for a phenomenon. A new observation may require modification of the theory.
D. is <em>incorrect</em>. Advancements in technology can provide new evidence that requires new explanations.
<u>Answer:</u> The net ionic equation is written below.
<u>Explanation:</u>
Net ionic equation of any reaction does not include any spectator ions.
Spectator ions are defined as the ions which does not get involved in a chemical equation. They are found on both the sides of the chemical reaction when it is present in ionic form.
The chemical equation for the reaction of ammonium carbonate and lead nitrate is given as:

Ionic form of the above equation follows:

As, ammonium and nitrate ions are present on both the sides of the reaction. Thus, it will not be present in the net ionic equation and are spectator ions.
The net ionic equation for the above reaction follows:

Hence, the net ionic equation is written above.