B. some species die out when environmental changes occur
Dopamine is a chemical released by neurons to send signals to other nerve cells. the brain includes several distinct dopamine pathways, one of which plays a major role in reward motivated behavior.
smoking is a habit, in a habit there is the cue, routine, and reward. with smoking the cue can be different things, most commonly stress or anxiety. the routine how you react to those cues, the reward is the chemical 'triggers' that are pulled inside you're brain leaving you feeling calm, happy, or relieved, etc.
Answer:
b) from a region of high pressure to a region of low pressure
Explanation:
Blood flow is measured in blood volume per unit time. It is the movement of blood through an organ, tissue or vessel. It is initiated when ventricles in heart contract leading to its ejection at high pressure. Major arteries receive this blood and they further transport it at high pressure to smaller arteries, arterioles and capillaries. Hence arteries have thick walls to withstand this pressure. The pressure decreases when blood reaches to veins hence their walls are not that thick. Hence, blood flows from a region of high pressure to a region of low pressure.
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa
You'll want to double check, but I think it's (a) cotyledon.
