Question

Give reason
veins have valves(1)mark ​

Answer 1

Answer:

ANSWER

The sentence uses the words 'was delivering' which indicates that it is in the past continuous tense. The passive form of the sentence must maintain this tense. Option A) contains the words 'is being delivered' which is in the present continuous tense. Hence, it is incorrect. Option B) is incorrect because it has 'is delivered' which is in the past tense. Option C) indicates that the lecture is complete and not an ongoing process as is indicated by the original sentence.

So, the most appropriate answer is D) A lecture was being delivered by our English teacher.

Answer 2

Unlike arteries, veins contain valves that ensure blood flows in only one direction. But, Arteries don't require valves because pressure from the heart is so strong that blood is only able to flow in one direction. Valves also help blood travel back to the heart against the force of gravity.

hope its helpful.