Answer:
D. A brown gas produced
Explanation:
When a chemical reaction occur, there are several changes that takes place such as change in color, odor change, formation of a gas, and formation of a precipitate etcetera.
In the given chemical reaction, two colorless gas (NO and O2) react together and form brown gas (NO2). So, the change of gas from colorless to brown gas is the evidence that shows chemical reaction occurred.
Hence, the correct option is "D. A brown gas produced".
Foods rich in iron include:
Red meat, pork and poultry.
Seafood.
Beans.
Dark green leafy vegetables, such as spinach.
Dried fruit, such as raisins and apricots.
Iron-fortified cereals, breads and pastas.
Peas.
It is A: a chemical reaction, due to the acid activity (acetic acid)
Answer:
D
Explanation:
You can immediately eliminate B and C. So between A and D, D is the best answer.
Answer: The statement is true
Explanation:
Natural selection, as its name implies refers to the choice of certain favorable traits such as resistance to diseases, bigger fruit size etc above lesser favorable traits such as easy susceptibility to diseases, small fruit size etc.
Hence, nature allows the traits that will help living organisms survive best in their environment to be passed down to new offsprings while it eliminates all other traits.
Thus, the statement is true
