Actually, golgi apparatus is specialised portion of smooth endoplasmic reticulum meant for cell secretion. it consists of flattened sacs or cisternae, vesicles and large secretary vacuoles.cisternae occur in small stacks .a golgi stack has a convex via face and a concave trans face.cis face is formative it receives vesicles from endoplasmic reticulum which join to form new cisternae of golgi body that's why it is associated with endoplasmic reticulum.

In the process of DNA replication, the DNA makes multiple copies of itself. It is a biological polymerization which proceeds in the sequence of initiation, elongation, and termination. The whole process takes place with the help of enzymes where DNA-dependent DNA polymerase being the chief enzyme.

The evidence suggests that land plants evolved from a line of filamentous green algae that invaded land about 410 million years ago during the Silurian period of the Paleozoic era. They are considered to be an ancestral to plants because both they both reproduce chlorophyll a/b, both have cell walls made of cellulose and in conjugation DNA is being shared between one cell to other without actually reproducing.

Bone

It is highly rigid connective tissue that forms the skeleton of vertebrates. They are the type of tissues which comprises of blood vessels and cells. Overall a newborn baby will have around 300 bones and is reduced to 206. The main function of bones are:

1. Serve as a storage of minerals.
2. Provide the structural support.
3. Protect the internal organs of the body.

Cartilage

It is thin, fibrous, flexible connective tissue, which is mainly found in the external ear, larynx, respiratory tract, and the articulating surface of the joints. These cartilages lack blood vessels, therefore the growth and development of these tissues are slower compared to the other tissues. Altogether there are three different types of cartilages and it includes:

1. Hyaline cartilage: It serves as a shock absorber and allows the smooth movement of the bones at joints. They are mainly found in the nose, respiratory tract, and joints
2. Fibrocartilage is found in the knee, and it is tough and inflexible.
3. Elastic cartilage is found in ear, epiglottis, and larynx. It is the most flexible cartilage.

Xylem and phloem are known as complex tissues as they are made up of more than one type of cells. These cells work in a coordinated manner, as a unit, to perform the various functions of the xylem and phloem.

Xylem helps in conducting water and minerals. It also provides mechanical support to plants. It is made up of the following components:

• Tracheids (xylem vessels and xylem tracheids)

• Xylem parenchyma

• Xylem fibres

Tracheids are elongated, thick-walled dead cells with tapering ends. Vessels are long, tubular, and cylindrical structures formed from the vessel members, with each having lignified walls and large central cavities. Both tracheids and vessels lack protoplasm. Xylem fibres consist of thick walls with an almost insignificant lumen. They help in providing mechanical support to the plant. Xylem parenchyma is made up of thin-walled parenchymatous cells that help in the storage of food materials and in the radial conduction of water.

Phloem helps in conducting food materials. It is composed of:

• Sieve tube elements

• Companion cells

• Phloem parenchyma

• Phloem fibres

Sieve tube elements are tube-like elongated structures associated with companion cells. The end walls of sieve tube elements are perforated to form the sieve plate. Sieve tube elements are living cells containing cytoplasm and nucleus. Companion cells are parenchymatous in nature. They help in maintaining the pressure gradient in the sieve tube elements. Phloem parenchyma helps in the storage of food and is made up of long tapering cells, with a dense cytoplasm. Phloem fibres are made up of elongated sclerenchymatous cells with thick cell walls.

Aestivation is the mode of arrangement of sepals or petals in a floral bud with respect to the other members of the same whorl.
There are four main types of aestivation. They are as follows:

1. Valvate aestivation: Sepals or petals in a whorl just touch one another. They do not overlap one another.

It is observed in <i>Calotropis.</i>

2. Twisted aestivation: One margin of the appendage overlaps the margin of the next appendage.

Such type of aestivation is seen in lady’s finger, china rose and cotton.

3. Imbricate aestivation:Margins of sepals or petals overlap one another but not in any particular direction.

It is seen in Gulmohar and <i>Cassia</i>.
4. Vexillary aestivation: It is also known as Papilionaceous type of aestivation.

There are five petals. The largest petal (called standard) overlaps the two
lateral petals (called wings) which further overlap the two smallest anterior petals (called keel).

Pea belongs to Fabaceae family. The flowers of the family Fabaceae have five sepals that are often fused and five clawed petals, upper posterior petal or the vexillum, two lateral free petals or wings, and two anterior petals or the keel.

Racemose Inflorescence

1. The formation of flowers is indefinite.

2. The main axis does not terminate in a flower and continuous to grow and forms flowers laterally.

3. The floral axis is monopodial.

Cymose Inflorescence

1. The formation of flowers is definite,

2. The main axis and its branches terminate in a flower.

3. The floral axis is multipodial

Placentation :- the arrangement of the ovules within the ovary is known as placentation.
placentation are of different types:-
1) Marginal
2) Axile
3) parietal
4) free central
5) basal

Marginal placentation :- In this, the placenta forms a ridge along the ventral suture of the ovary and ovules are borne on the ridge.
e.g --> pea

Axile placentation :- In this , the placenta is Axile and ovules are attached to it .
e g- China rose , tomato , lemon

Parietal placentation :- in this , the ovules develop on inner wall of the ovary or on peripheral part.
e.g -> mustard , Argemone

Free central placentation :- In this , the ovules are borne on central axis and septa are absent.
e.g-> Dianthus and Primrose.

basal placentation :- in this , placenta develop at base of ovary & single ovule is attached to it.

e g -> sunflower , marigold.

The root tip can be divided into three zones: a zone of cell division, a zone of elongation, and a zone of maturation. The zone of cell division is closest to the root tip and is made up of the actively-dividing cells of the root meristem, which contains the undifferentiated cells of the germinating plant.

Keys are pairs of two contrasting characters. Selection of one character leads to rejection of another character while identifying a particular species or genera or family and so on.

For example presence or absence of hair on body can give a clue if an animal belongs to mammalian or not.

The nervous tissue has two outstanding properties : excitability and conductivity.
(a) Excitability : It is the ability of the nerve cells and fibres to enter into an active state called the state of excitation in response to a stimulus. Excitation arises at the receptors on account of various stimuli such as light, temperature, chemical, electrical or pressure which constantly act on the organisms.
(b) Conductivity : The excitation does not remain at
the site of its origin. It is transmitted along nerve fibres. The transmission of excitation in a particular direction is called conductivity

Spermatogenesis is a concerted sequence of events during maturation of spermatogonia into spermatozoa. The process involves differential gene-expression and cell-cell interplay regulated by the key endocrine stimuli, i.e., follicle-stimulating hormone (FSH) and luteinizing hormone (LH)-stimulated testosterone. In women, this hormone stimulates the growth of ovarian follicles in the ovary before the release of an egg from one follicle at ovulation. It also increases oestradiol production. In men, follicle-stimulating hormone acts on the Sertoli cells of the testes to stimulate sperm production (spermatogenesis).

Metagenesis is the phenomenon in which one generation of certain plants and animals reproduce asexually, followed by the sexually reproducing generation. Both the forms are diploid in metagenesis hence, it is the false alternation of generation. Coelenterates exhibits metagenesis (e.g., Obelia) where polyp form alternates with medusa in its life cycle.

Meristem : A meristem or meristematic tissues is a group of cells that are in a continuous state of division and thus continuously produce new cells. Location and function of meristems : On the basis of location and function, the meristems are of the following types:
(1) Apical meristems : These are present at the apices of stems, roots and branches. The activity of the apices of stems, adds to the length of the plant or its part.
(2) Intercalary meristems : These meristems are intercalated in between the permanent tissues. They may be present either at the base of the internode as in the stem of various grasses and wheat; or at the base of the leaf as in pinus; or at the base of a node as in mint. The activities of these meristems also add to the length of the plant or its organs.
(3) Lateral meristems : These meristems are present along the side of the stem. These include cambium and cork cambium. The activity of lateral meristems adds to the thickness of the plant. A meristem or meristematic tissues is a group of cells that are in a continuous state of division and thus continuously produce new cells. Location and function of meristems : On the basis of location and function, the meristems are of the following types:
(1) Apical meristems : These are present at the apices of stems, roots and branches. The activity of the apices of stems, adds to the length of the plant or its part.
(2) Intercalary meristems : These meristems are intercalated in between the permanent tissues. They may be present either at the base of the internode as in the stem of various grasses and wheat; or at the base of the leaf as in pinus; or at the base of a node as in mint. The activities of these meristems also add to the length of the plant or its organs.
(3) Lateral meristems : These meristems are present along the side of the stem. These include cambium and cork cambium. The activity of lateral meristems adds to the thickness of the plant.

A mammary gland is an exocrine gland in humans and other mammals that produces milk to feed young offspring. Mammals get their name from the Latin word mamma, "breast". In a few mammalian species, male lactation can occur. Functionally, the mammary glands produce milk; structurally, they are modified sweat glands. Mammary glands, which are located in the breast overlying the pectoralis major muscles, are present in both sexes, but usually are functional only in the female.

The chromatids are moved towards the pole at a speed of 1 mm/minute. About 30 ATP molecules are used to move one chromosome from equator to pole.