Answer:
1. C. Ecosystem
Explanation:
An ecosystem consist of living and nonliving things
Answer:Valves stop blood flowing backwards
Explanation: Valve are flags of tissue that control the direction of the blood in our heart.,it prevent the backwards flow of blood. valves regulate blood from flowing back into the atria.The right and left atrio-ventricular valves prevent blood from flowing backwards into atria. When the ventricle is full,the valve prevent backwards flow of blood.
Answer:
The nervous system releases neurotransmitters at synapses at specific target cells & The endocrine system reacts more slowly to stimuli, often taking seconds to days.
Explanation:
The nervous system is very specific with where the neurotransmitters go so they will affect target cells. The endocrine system is slower than the nervous system because the hormones travel through the blood so it takes much longer to reach the designated area.
The answer is B: Response to stimuli
what response to stimuli means is that the organism reacts to something around it
the venus flytrap wouldn't just randomly close for no reason
it had to sense the fly, and react by closing.
it's not permeability because permeability means allowing things to pass through like soaking up water
unless your teacher is referring to absorbing the nutrients of the dead fly after it's been killed
but I don't think that's what this question is about
:)