1. The cell wall has lignin (hard substance): to prevent the xylem vessel from collapsing and withstand high pressure.
2. The absence of protoplasm (nucleus + cytoplasm) and cross wall: to allow water to move through the lumen easily.
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Answer:
A. is correct
Explanation:
Low-pressure systems are associated with volatile weather conditions like clouds and rain. This is exactly what A says. Hope this helps :)
Answer:
It discusses Pollution levels in the Air
Explanation: Air can be hazardous to those lungs that are weak. They have something called an Air Quality Alert to warn those with weak lungs to take precautions. Hope this helped!
Answer:
Option-D
Explanation:
Plasmodesmata are the plasma membrane lined pores present in the cells of the plants. Inside these pores runs a closed tubelike structure which is an extension of the endoplasmic reticulum.
The plasmodesmata allows cell to cell communication which involves symplast mode of transport that is through its cytoplasm.
The small water soluble molecules like amino acid and sugars can easily pass through these plasmodesmata via diffusion. The large molecules can be transported through these plamodesmata through selective diffusion.
Thus, Option-D is the correct answer.
The flow of energy moves through living organisms via the food chain. A food chain is a diagram which shows how every living thing gets energy to live. Plants use the sun, nutrients in the soil and water to generate energy. Herbivores eat the plants to generate energy to survive. Carnivores eat the herbivores to generate energy.
<span>Matter moves through the biosphere by being cycled through various organic and inorganic stages. They are neither created nor destroyed. The biosphere is known as a closed system so no elements can escape. They are continually being recycled. </span>