Most railroad tracks are built from pieces of steel supported by wooden ties, and laid with a gap between the ends. Why are these gaps provided in railway tracks?

Explanation:

The reasons are:

Firstly , the thermal expansion of solid at higher temperatures.

During the summer season, the steel tracks may expand due to thermal expansion and if gaps are not laid the tracks will bend and lead to accidents.

Secondly, imbibition of water during rainy season.

During the rainy season the wooden tracks will imbibe water and swell. If gaps are not provided, this may result irregular levels of railway track. This may prove very dangerous and lead to railway accident.

b - the respond is innate and varies over time.

good luck!

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)