When babies enter the second year
They crawl vigorously, walk, and use their developmental limits to explore rules and boundaries set by the parent. When playing a complex sport such as tennis, the child will provide little attention, increased memory but less thinking to help in exploring the game. For instance, a child would have less attention as he would not be interested in the game but instead, he would be looking for a relative or food. On the memory, the child would try to hit the ball, probably because he saw the opponent doing it, but the problem is that the kid would hit without thinking on where to direct the ball.
On the other hand, a five years child
They are more developed, confident and self-independent. Therefore, in a complex game like tennis, the child is likely to have higher attention but easily disrupted by other activities around him. For instance, in some cases, the child has higher chances of catching the ball instead of hitting. Nonetheless, the same kid shall have a higher memory to know where to direct the ball, but the thinking capacity would be reduced as the child would push forward without thinking of a real challenge against the opponent.
I would apply what I have learnt this week
By helping young children at the age of two to avoid complex activities as they may not develop the required attention. For instance, a young child may not be interested in tennis, and therefore he would not be curious not acquire his attention. Nonetheless, I can use non-complex objects to train him or her by asking "what do you think is this," this would trigger their curiosity and increase the memory. After explaining the case to the child, he becomes more curious and increases his thinking levels.