The xylem in plants are responsible for
(a) transport of water. (c) transport of amino acids.
(b) transport of food. (d) transport of oxygen.
(a) Transport of water
Xylem is a complex tissue composed of living and non-living cells. The conducting cells are mostly non- living and includes two types of tracheary elements- tracheids and vessel elements. Water and minerals from the soil enter into the plant through the root and then through root cortex and finally get passed into the xylem, moves upward into the leaves. The upward movement of the water and the minerals from roots to the aerial parts of the plant against the gravitational force through the xylem is known as ascent of the sap.
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
How is the amount of urine produced regulated?
What are the different ways in which glucose is oxidised to provide energy in various organisms?
What criteria do we use to decide whether something is alive?
The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(a) cytoplasm. (c) chloroplast.
(b) mitochondria. (d) nucleus.
What are the differences between autotrophic nutrition and heterotrophic nutrition?
What are the components of the transport system in highly organised plants?
What would be the consequences of a deficiency of haemoglobin in our bodies?
What are outside raw materials used for by an organism?
What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
What is a good source of energy?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What changes can you make in your habits to become more environment-friendly?
What is the difference between a reflex action and walking?
What is the importance of DNA copying in reproduction?
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Why should a magnesium ribbon be cleared before burning in air?
Define the principal focus of a concave mirror.
You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
What will happen if we kill all the organisms in one trophic level?
What is meant by saying that the potential difference between two points is 1 V?
What are the changes seen in girls at the time of puberty?
What chemical process is used for obtaining a metal from its oxide?
Calculate the number of electrons constituting one coulomb of charge.
Choose the correct option.
A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each
(a) two revolutions (b) one revolution
(c) half revolution (d) one-fourth revolution
When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.
Find the focal length of a lens of power – 2.0 D. What type of lens is this?
What will be the formula and electron dot structure of cyclopentane?
What kind of mirror – concave, convex or plain – would be best suited for use in a solar cooker? Why?