Answer:
The correct answer will be option-B.
Explanation:
The plant tissues are composed of three types of cells: parenchyma, collenchyma and sclerenchyma.
The parenchyma and collenchyma remain alive at their maturity but sclerenchyma loses their protoplasm and become dead. These cells deposit lignin in their secondary walls and form hard tissues of the plant-like hard shell of a coconut. Sclerenchyma provides mechanical strength to the plant.
Thus, Option-B is the correct answer.
Answer:
Internal and external regulators are two types of proteins that regulate the cell cycle. Internal regulators allow the cell cycle to proceed only after certain events occur. External regulators speed up or slow down the cell cycle.
Explanation:
I hope this helps :)
The correct answer is option D.
If a girl is standing in front of a smooth surface from which a sound is reflected, the girl may hear two similar sets of sounds if she is also near the source of the sound.
For proper reflection of all sorts of energy waves, a hard flat surface is preferable. This helps to reflect waves without losing energy. Hard and smooth surfaces are best for travelling of sound waves because sound is related to pressure.
