The correct answer is D. They have two successive sets of teeth including milk teeth and permanent adult teeth
Explanation:
In biology, a diphyodont is an animal that has two different sets of teeth, this often means the animal has a set of baby teeth that are later replaced by permanent teeth, this occurs in most mammals including humans. Additionally, diphyodont differ from other types of animals that have either only one set of teeth (monophyodonts), for example, toothed whales or change their teeth permanently (polyphyodont), for example, crocodiles. Thus, mammals are diphyodont because "they have two successive sets of teeth including milk teeth and permanent adult teeth".
Active transport: Movement of materials across a membrane that requires an input of energy from a cell. Movement of material against the concentration gradient (from low concentration to high concentration)
Passive transport: Movement of materials across a membrane that does not require energy from the cell. Movement of material against the concentration gradient (from high concentration to low concentration)
The pH scale measures how acidic or basic a substance is. The pH scale ranges from 0 to 14. A pH of 7 is neutral. A pH less than 7 is acidic. A pH greater than 7 is basic.
The air that organisms breathe contains particulate matter such as dust, dirt, viral particles, and bacteria that can damage the lungs or trigger allergic immune responses.
