What chemical ion is responsible for initiating the contraction of a muscle fiber?

While both systems maintain homeostasis, how does the nervous system differ from the endocrine system?

How many synapses are crossed in a single reflex arc during a muscle stretch reflex?

A measurement of how common one species is compared to another species is referred to as

Sunflower plants have smooth and fleshy stems. Based on these characteristics, which type of plant could it be? A.) Herbaceous B.) Woody C.) Monocot

Which statement best describes heat and thermal energy? A:They are different words for the same thing. B: They represent different concepts. C: Heat is what happens when thermal energy stops moving between substances.

What type of bacteria causes environmental change

Contrast a food chain with a food web, and include the total % of energy which is conserved between each level of a food chain

What happens when the lungs recoil? A. Inspiration occurs. B. Internal respiration occurs. C. Ribs and diaphragm muscles contract. D. Expiration occurs.

Which of these is NOT a reproductive isolating mechanism? geographic temporal behavioral all of these are reproductive isolating mechanisms

What type of intrusive igneous rock texture has the largest crystals