The answer is B . just think like foot ball players or other characteristics.
A control group in a scientific experiment is a group separated from the rest of the experiment, where the independent variable being tested cannot influence the results. This isolates the independent variable's effects on the experiment and can help rule out alternative explanations of the experimental results.
Answer: A closed circulatory system and an excretory system consisting of tubular nephridia
Explanation:
Hibernation helps animals survive the changing seasons. Foods that bears eat, such as berries and flowers, are much less available during cold winter months. When they hibernate, bears enter a deep sleep. ... While they sleep, the bears can survive because their bodies live off of their stored fat or food.
During hibernation, the animal’s body temperature, heart rate and breathing rate all drop to significantly lower levels. Animals do this to survive the winter because the weather is cold and food is scarce. It is advantageous because these animals can quite literally shut themselves off for weeks at a time rather than try and survive through harsh weather conditions.
While many people think bears are hibernators, they actually participate in a similar, though not exact, practice. Instead of hibernating, bears fall into a deep sleep called torpor. During torpor, heart rate and breathing rate decreases, body temperature reduces slightly and bears do not eat or release bodily waste. Bears can sleep more than 100 days without eating, drinking, or passing waste!
Bears sleep in dens that they make themselves, as well as in hollow trees, caves and dens built by other bears. A den can be built in 3–7 days, however, the timing of den building varies from bear to bear. While some bears build their dens months before hibernation season, others choose to excavate their dens.
These animals can dramatically drop their body temperature to below freezing—salty body fluids work to prevent tissue crystallization in particularly cold temperatures.
So really, animals that are true hibernators don’t actually sleep through the entire winter.
The urea produced by their fat metabolism is broken down and the nitrogen is re-used by the bear to rebuild protein.
Answer:
the last option is the best
Explanation:
no idea that will ever pass without disagrement from other scientists who generate and defend the opposite ideas
