a. The arrangement of leaves on stems is called phyllotaxis. The fol.pdf

a. The arrangement of leaves on stems is called phyllotaxis. The following are the types of
arrangement:
* Alternate: Leaves are arranged alternate with one leaf per node. They are arranged alternate on
the side of stem or in a spiral fashion around the stem. Examples: Berberis thungergii, Cotinus
coggygria
* Opposite: A pair of leaves occur at each node. eg: Catalpa Sp., Cornus florida, Cornus mas
* Whorled: Three or more leaves arise form the same node to form whorls of leaves along the
stem. eg: Alstonia scholaris, Allamanda cathartica
b.
Pinnate venation: From a central main vein, leaf veins are produced on either side and extend
from the petiole to the leaf tip. Eg: Mangifera Indica
Palmate: The main veins radiate from a central point at the petiole, and each main vein extends
from the petiole to the tip of a lobe. Eg: Hibiscus rosa sinensis
Reticulate: it is also called net-venation in which leaves have many branches of major and minor
veins. Eg: Corainder, Rose
Parallel: The leaves extend parallel from the petiole to the tip of the leaf. It is characteristic of
monocots. Eg: Maize, Wheat
6.
Living organisms lock nutrients in their macromolecules. The dead and decaying organisms,
through microbial action, release these locked nutrients back into the soil. Certain components of
the organic matter cannot be degraded and remains as humus. This humus improves the
characteristics of soil, it improves the water retention capacity of the soil, makes it more fertile,
and prevents soil erosion.
Solution
a. The arrangement of leaves on stems is called phyllotaxis. The following are the types of
arrangement:
* Alternate: Leaves are arranged alternate with one leaf per node. They are arranged alternate on
the side of stem or in a spiral fashion around the stem. Examples: Berberis thungergii, Cotinus
coggygria
* Opposite: A pair of leaves occur at each node. eg: Catalpa Sp., Cornus florida, Cornus mas
* Whorled: Three or more leaves arise form the same node to form whorls of leaves along the
stem. eg: Alstonia scholaris, Allamanda cathartica
b.
Pinnate venation: From a central main vein, leaf veins are produced on either side and extend
from the petiole to the leaf tip. Eg: Mangifera Indica
Palmate: The main veins radiate from a central point at the petiole, and each main vein extends
from the petiole to the tip of a lobe. Eg: Hibiscus rosa sinensis
Reticulate: it is also called net-venation in which leaves have many branches of major and minor
veins. Eg: Corainder, Rose
Parallel: The leaves extend parallel from the petiole to the tip of the leaf. It is characteristic of
monocots. Eg: Maize, Wheat
6.
Living organisms lock nutrients in their macromolecules. The dead and decaying organisms,
through microbial action, release these locked nutrients back into the soil. Certain components of
the organic matter cannot be degraded and remains as humus. This humus improves the
characteristics of soil, it improves the water retention capacity of the soil, mak.

1. a. The arrangement of leaves on stems is called phyllotaxis. The following are the types of
arrangement:
* Alternate: Leaves are arranged alternate with one leaf per node. They are arranged alternate on
the side of stem or in a spiral fashion around the stem. Examples: Berberis thungergii, Cotinus
coggygria
* Opposite: A pair of leaves occur at each node. eg: Catalpa Sp., Cornus florida, Cornus mas
* Whorled: Three or more leaves arise form the same node to form whorls of leaves along the
stem. eg: Alstonia scholaris, Allamanda cathartica
b.
Pinnate venation: From a central main vein, leaf veins are produced on either side and extend
from the petiole to the leaf tip. Eg: Mangifera Indica
Palmate: The main veins radiate from a central point at the petiole, and each main vein extends
from the petiole to the tip of a lobe. Eg: Hibiscus rosa sinensis
Reticulate: it is also called net-venation in which leaves have many branches of major and minor
veins. Eg: Corainder, Rose
Parallel: The leaves extend parallel from the petiole to the tip of the leaf. It is characteristic of
monocots. Eg: Maize, Wheat
6.
Living organisms lock nutrients in their macromolecules. The dead and decaying organisms,
through microbial action, release these locked nutrients back into the soil. Certain components of
the organic matter cannot be degraded and remains as humus. This humus improves the
characteristics of soil, it improves the water retention capacity of the soil, makes it more fertile,
and prevents soil erosion.


Solution

a. The arrangement of leaves on stems is called phyllotaxis. The following are the types of
arrangement:
* Alternate: Leaves are arranged alternate with one leaf per node. They are arranged alternate on
the side of stem or in a spiral fashion around the stem. Examples: Berberis thungergii, Cotinus
coggygria
* Opposite: A pair of leaves occur at each node. eg: Catalpa Sp., Cornus florida, Cornus mas
* Whorled: Three or more leaves arise form the same node to form whorls of leaves along the
stem. eg: Alstonia scholaris, Allamanda cathartica

2. b.
Pinnate venation: From a central main vein, leaf veins are produced on either side and extend
from the petiole to the leaf tip. Eg: Mangifera Indica
Palmate: The main veins radiate from a central point at the petiole, and each main vein extends
from the petiole to the tip of a lobe. Eg: Hibiscus rosa sinensis
Reticulate: it is also called net-venation in which leaves have many branches of major and minor
veins. Eg: Corainder, Rose
Parallel: The leaves extend parallel from the petiole to the tip of the leaf. It is characteristic of
monocots. Eg: Maize, Wheat
6.
Living organisms lock nutrients in their macromolecules. The dead and decaying organisms,
through microbial action, release these locked nutrients back into the soil. Certain components of
the organic matter cannot be degraded and remains as humus. This humus improves the
characteristics of soil, it improves the water retention capacity of the soil, makes it more fertile,
and prevents soil erosion.