Please answer as many questions as you can on Biology?

Question

Im studying for a test and was wondering these answers...thx....
DEALING WITH ROOTS.

1. explain how root tip moves through soil

2.what is a stele

3.Why are old roots and stems identical in terms of tissues and functions.

4.Why are there no root hairs on old sections of the root

5. Ehy do biologists associate downward material movement with xylem and upward with phloem.

6.Explain how vascular cambium produces more xylem each year and how it contributes to secondary development

Answer 1

1. The cells of the root tip multiply in the apical meristem just behind the root cap. These cells move up into the zone of elongation and then into the maturation zone pushing the root tip deeper into the ground.

2. The central cylinder of the root containing everything from the endodermis inward.

3. Old roots and stems are mainly constructed of vascular tissue xylem and phloem and very little else.

4. As the roots get thicker they lose their epidermal area made up of single celled root hairs.

5. You got it backwards. The xylem is responsible for taking water and minerals up through the plant. Phloem carries the processed food downwards to the stems and roots.

6. Vascular cambium is meristematic tissue. Mitosis occurs here constantly. The cells to the back of this tissue form xylem and those to the front the phloem. The accumulation of the xylem forms rings causing the tree to grow in thickness.

Answer 2

1. Because of the roots caps that dig deeper to get water.
2.Stele is the central part of stems and roots: the cylindrical core of the stem and roots of a plant that contains the sap-conducting vascular tissues and varying amounts of packing tissue pith.
3. Because they just use each other as transporters.
4. Because of decomposition.
5. Because plants need water so it goes up while minerals are stored below. That's the reason there is dew.
6. For minerals to be used because without minerals plants cannot develop.

Answer 3

sre u sure that u hav searched for these?
still i would answer a few.
1.by the combined effect of geotropism and hydrotropism
2.anatomically, every tissue inside the endodermis comprises the stele.
3.
4.
5.because of experiments using c14
6.this is a very long answer and hence you must look it up in a book.

Answer 4

no