Answer:
The second option.
Explanation:
We're trying to test the amount of bleach that has an effect on the stain so that is the altered variable.
The 2nd option uses different amounts of bleach to clean the same amount of stain.
If you choose the other options, people can argue that the bigger stain would be harder to clean with one cup of bleach, whereas the small stain gets two cups or the other way around.
It's not an effective way to see if the amount of bleach has an effect on stain removal.
Answer:
Birds can keep themselves warn without any external heat source which is not the case with reptiles and amphibians
Explanation:
Birds are able to generate heat means they are endothermic. They generate heat through various metabolic processes. They have air pockets beneath their feathers to insulate their bodies during cold temperatures. Feathers which are modified reptilian scales help birds to streamline their exterior body and structure feathers in a way that it insulates the body.
Explanation:
They differ when they have the same chemical composition but the way in which they are arranged or put together is different.
Answer:
The used up all their resources too fast and weren't able to regrow them in time; they eventually basically killed each other off.
Explanation:
The answer is the sphenoid bone
