Food is usually kept from entering your trachea by the Epiglottis
The correct answer is option-D
The fossil record shows species suddenly appearing and disappearing. When one species goes extinct, another one usually takes its place. It provides with the snapshots of the past. It shows the changes over the past four billion years. It maybe unclear at parts but it does provide evidence that life is old and over time has changed. By studying fossil record the relation of different plants and animals can be figured out and it also tells us how old life is on earth. We can learn about extinct species and find out the reasons as well behind there extinction.
The correct answer is <span>D. circulatory, respiratory, nervous, endocrine
The other systems mentioned in the first three examples don't maintain oxygen levels at that body strain level.</span>
The fallopian tubes, also known as uterine tubes.
