When a man has an erection does he releases sperm

Not necessarily.

Explanation:

An erection is caused by blood flow to the penis. A man can get an erection just by seeing a woman or hearing language that turns him on or excites him. A young man who is not experienced in controlling an erection may release sperm in a spontaneous ejaculation but more experienced men would not likely ejaculate without more stimulation, such as masturbation.

1. a host loses nutrients to a parasite

2. a parasite only benefits when the host is alive (cause if the host dies the parasite dies with it )

3. producers to consumers

4. the tapeworm is a parasite

5. they convert energy from the sun (photosynthesis)

6. sunflower-robin (i think im 80% sure)

7. producer

8. consumer

9. prey

10. fresh water snails ( cause the green algea is the producer and the snails are the primary consumers and the small fish consumer so is the big fish)