1. The mass number and atomic numbers of carbon-12 are 12 and 6, while those of carbon-13 are 13 and 6.
2. The mass number and atomic numbers of carbon-12 are 12 and 6, while those of carbon-13 are 13 and 12.
3. The mass number and atomic numbers of carbon-12 are 12 and 6, while those of carbon-12 are 13 and 13.
4. The mass number and atomic numbers of carbon-12 are 12 and 12, while those of carbon-13 are 13 and 12.

1. Hydrogen bonds and van der Waals interactions form weak associations between molecules, providing the necessary shape and structure of DNA and proteins to function in the body.
2. Hydrogen bonds and van der Waals interactions form strong associations between molecules, providing the necessary shape and structure of DNA and proteins to function in the body.
3. Hydrogen bonds and van der Waals interactions form weak associations between different molecules, providing the necessary shape and structure for acids to function in the body.
4. Hydrogen bonds and van der Waals interactions form strong associations between same molecules, providing the necessary shape and structure for acids to function in the body.

1. Group 1 and Group 17
2. Group 1 and Group 14
3. Group 14 and Group 18
4. Group 1 and Group 18

1. Insects can walk on water because of its high surface tension.
2. Insects can walk on water because it is a polar solvent.
3. Insects can walk on water because they are less dense than water.
4. Insects can walk on water because they are denser than water.

1. Buffers absorb excess hydrogen and hydroxide ions to prevent increases or decrease in pH. An example is the bicarbonate system in human body.
2. Buffers absorb excess hydrogen ions to prevent increases or decreases in pH. An example is the bicarbonate system in the human body.
3. Buffers absorb excess hydroxide ions to prevent increases or decreases in pH. An example of that is the bicarbonate system in the human body.
4. Buffers absorb excess hydrogen and hydroxide ions to prevent increases or decreases in pH. An example of that is carbonate system in human body.

1. First, the lower density of water as a solid versus a liquid allows ice to float, forming an insulating surface layer for aquatic life. Second, the high specific heat capacity of water insulates aquatic life or bodily fluids from temperature changes. Third, the high heat of vaporization of water allows animals to cool themselves by sweating.
2. First, the higher density of water as a solid versus a liquid allows ice to float, forming an insulating surface layer for aquatic life. Second, the high specific heat capacity of water insulates aquatic life or bodily fluids from temperature changes. Third, the low heat of vaporization of water allows animals to cool themselves by sweating.
3. First, the lower density of water as a solid versus a liquid allows ice to float, forming an insulating surface layer for aquatic life. Second, the low specific heat capacity of water insulates aquatic life or bodily fluids from temperature changes. Third, the high heat of vaporization of water allows animals to cool themselves by sweating.
4. First, the lower density of water as a solid versus a liquid allows ice to float, forming an insulating surface layer for aquatic life. Second, the low specific heat capacity of water insulates aquatic life or bodily fluids from temperature changes. Third, the low heat of vaporization of water allows animals to cool themselves by sweating.

1. The pH scale ranges from 0 to 14, where anything below 7 is acidic and above 7 is alkaline. The bicarbonate system in the human body buffers the blood.
2. The pH scale ranges from 0 to 14, where anything below 7 is alkaline and above 7 is acidic. The bicarbonate system in human body buffers the blood.
3. The pH scale ranges from 0 to 7, where anything below 7 is acidic and above 7 is alkaline. Water in the human body buffers the blood.
4. pH scale ranges from 0 to 7, where anything below 4 is acidic and above 4 is alkaline. Water in the human body buffers the blood.

1. Carbon can form up to four covalent bonds, allowing it to form long chains.
2. Carbon can form more than four covalent bonds, allowing it to form long chains.
3. Carbon can form more than four covalent bonds, but can only form short chains.
4. Carbon can form up to four covalent bonds, but can only form short chains.

What property of carboxyl makes carboxyl containing molecules hydrophilic? Which macromolecules contain carboxyl?

1. Carboxyl groups release H⁺, making its parent molecule hydrophilic. It is found amino acids and fatty acids.
2. Carboxyl groups absorb H⁺ ion, making its parent molecule hydrophilic. It is found in phospholipids and triglycerides.
3. Carboxyl groups release OH⁻, making its parent molecule hydrophilic. It is found in phospholipids phosphates and triglycerides.
4. Carboxyl groups release OH⁻, making its parent molecule hydrophilic. It is found in phospholipids and DNA.

1. Saturated triglycerides contain single bonds and are solids at room temperature, while unsaturated triglycerides contain double bonds and are liquids at room temperature.
2. Saturated triglycerides contain double bonds and are solids at room temperature, while unsaturated triglycerides contain single bonds and are liquids at room temperature.
3. Saturated triglycerides contain single bonds and are liquids at room temperature, while unsaturated triglycerides contain double bonds and are solids at room temperature.
4. Saturated triglycerides contain double bonds and are liquids at room temperature, while unsaturated triglycerides contain single bonds and are solids at room temperature.