Assertion and reasoning-type questions have one assertion (A) and one reason (R). We must first determine whether the statement is true. If the statement is true, we must next determine whether the reason correctly explains the assertion.
First, we will consider the statement of Assertion:
All teaching implies learning because teaching and learning take place simultaneously, if the teaching process if going on that means the knowledge is being imparted and the learner will definitely gain the knowledge. learning depends on the quality of teaching to a great extent. Students pay attention to what they are taught.
Hence, The statement in assertion is true.
Now we will consider the statement of Reason:
Learning to be useful must be derived from teaching is not the correct statement because of all learning outcomes from Personal characteristics, Academic characteristics, Social/emotional characteristics, and Cognitive characteristics. A learner can learn by himself/herself through the internet, online lessons, books, etc, so all learning is not the result of teaching only. So, it does not like that the learning must be derived from teaching only.
Hence, the statement provided in the reason is false.
Hence, we conclude that (A) is true, but (R) is false.