Answer:
1. Purines
2. States that DNA composition varies among species
3. Hydrogen Bond
4. Purines
<em>Answer to #2 is a little iffy </em>-- sorry
Explanation:
Pyrmidines have two rings
Purines have one ring
Complementary bases are connected by hydrogen bonds.
Answer:
Option C
Explanation:
Option
A. 6440 mL/min
B. 4340 mL
C. 3500 mL/min
D. 2940 mL/min
Solution
It is required to find the minute ventilation which is equal to the product of rate of breathing and the total amount of gas being inhaled or exhaled per breathe. Let this minute ventilation be denoted by "
"
Thus,

where TD is the tidal volume and Br is the rate of breathing
Substituting the given values we get

We will now reduce the air held in the conducting zone of respiratory system
Air held per breathe 
Total Air held

Amount of fresh air one can breathe in and out every minute

Hence, Option C is correct
The answer is C. Adapting to changes in the environment
1. Reduced production of waste materials
2. Increased reuse of older materials
3. Use more renewable sources of energy
4. Decrease the rate of fires through alternate means of warmth
5. Burn down less forests and find better means of farming
Answer:
so that whenever we get hurt or something happens our system can grow back like a scar.Everyday it is rebuilding new cells as well as it is always throwing away cells that don't work anymore