It is observed thatdeficiency of a particular element showed itssymptomsinitially in older leaves and then in younger leaves. Name two elemtns which are highly mobile and two which are relatively immobile.

It is observed that deficiency of a particular element showed its symptoms initially in older leaves and then in younger leaves. Does it indicate that the element is actively mobilized or relatively immobile?

It is observed that deficiency of a particular element showed its symptomsinitially in older leaves and then in younger leaves. How is the aspect of mobility of elements important to horticulture and agriculture?

Answer the following questions in one sentence each : Name two elements in which the K and L shells of an atom are completely filled with electrons.

Answer the following questions: Observes the given figure of reactivity Series of metals and answer the following questions : Name two metals which react with water.

Mendeleev predicted the existence of certain elements not know at that time. He named two of these elements as eka-aluminium and eka-silicon. a. Name the elements which have taken the place of these elements. b. Mention the group and period of these elements in the modern periodic table. c. Which one of these two elements is a metalloid? d. How many valence electrons are present in eka-silicon? e. Eka-aluminium forms a chloride. What is its formula?

Observe the following diagram and write the answers of the following question Write the names of any two elements from the diagram which do not take part in chemical reaction.

Answer the following questions: Observe the following diagram and write the answer the following questions: Write the names of any two elements from the diagram which do not take part in chemical reaction.

Read the following paragraph and answer the following questions given below it : Construction of a compound microscope : (i) Acompound microscope consists of a metal tube fitted with two convex lenses at the two ends. These lenses are called the objective lens ( the lens directed towards the object ) and the eyepiece ( the lens directed towards the eye ). Both the lenses are small in size , but the cross section of the objective lens has a short focal length . the focal length of the eyepiece is more than that of the objective lens . (ii) The metal tube is mounted on a stand . thr principal axes of the objective lens and the eyepiece are along the same line . The distance between the object and objective lens can be changed with a screw . It is possible to change the distance between the objective lens and the eyepiece. Working : (i) The object to be observed is illuminated and placed in front of the objective lens. slightly beyond the focal length of the objective lens. it's real , inverted and enlarged image is formed by the objective lens on the other side. (ii) This intermediate image lies with in the focal length of the eyepiece. It serves as an object for the eyepiece. The eyepiece works as a simple microscope . the final image is virtual, highly enlarged and inverted with respect to the original object . It can be formed at the minimum distance of distinct vision from the eyepiece . The final image is observed by keeping the eye close to the eyepiece. Use: This microscope is used to observe blood cells , microorganisms , etc. State which distance is adjusted to observe the object with a compound microscope ?

Read the following paragraph and answer the following questions given below it : Construction of a compound microscope : (i) Acompound microscope consists of a metal tube fitted with two convex lenses at the two ends. These lenses are called the objective lens ( the lens directed towards the object ) and the eyepiece ( the lens directed towards the eye ). Both the lenses are small in size , but the cross section of the objective lens has a short focal length . the focal length of the eyepiece is more than that of the objective lens . (ii) The metal tube is mounted on a stand . thr principal axes of the objective lens and the eyepiece are along the same line . The distance between the object and objective lens can be changed with a screw . It is possible to change the distance between the objective lens and the eyepiece. Working : (i) The object to be observed is illuminated and placed in front of the objective lens. slightly beyond the focal length of the objective lens. it's real , inverted and enlarged image is formed by the objective lens on the other side. (ii) This intermediate image lies with in the focal length of the eyepiece. It serves as an object for the eyepiece. The eyepiece works as a simple microscope . the final image is virtual, highly enlarged and inverted with respect to the original object . It can be formed at the minimum distance of distinct vision from the eyepiece . The final image is observed by keeping the eye close to the eyepiece. Use: This microscope is used to observe blood cells , microorganisms , etc. In a compound microscope , which lens has greater focal length ?

In eukaryotes, the process of division of a somatic parent cell into two daughter cells is known as mitosis. During the M or mitosis phase of a cell cycle, the chromosomes present in the nucleus are separated into two identical sets, which eventually form two daughter nuclei. This is followed by cytokinesis. Onion root tips are most commonly used to observe the different stages of mitosis in the laboratory. Each onion cell contains a total of eight chromosomes. DNA specific stains are used to visualise these chromosomes in different phases of mitosis. Name the stain that can be used to observe the different phases of mitosis.