Consider all organisms that have circulatory systems similar to those of humans. Is there any "ideal" proportion between the sizes of the circulatory system and the entire organism? How
- in affect the efficiency of the organ system?

What are the student's observations and inferences before he starts his investigation?

Which of the following best describes the expensive tissue hypothesis? brains require more energy, so the gut had to be reduced, and larger brains and tool use led to higher quality diets. increasing body size means that homo neanderthalensis had to include more fat in its diet. brains require more energy, so the gut had to be reduced as brains got bigger. brains require more fat, so the gastrointestinal viscera (gut) had to expand, and hands were needed to acquire more food.

This is the nitrogenous base only found in rna