Some characteristic features of Euglenoids are as follows.

• Euglenoids (such as Euglena) are unicellular protists commonly found in fresh water.

• Instead of cell wall, a protein-rich cell membrane known as pellicle is present.

• They bear two flagella on the anterior end of the body.

• A small light sensitive eye spot is present.

• They contain photosynthetic pigments such as chlorophyll and can thus prepare their own food. However, in absence of light, they behave similar to heterotrophs by capturing other small aquatic organisms.

• They have both plant and animal-like features, which makes them difficult to classify and hence they are called as connecting link between plants and animals.

Algae reproduce asexually by a variety of spores such as ,

1) Zoospores : these are flagelated , often with an eyespot. Normally these are formed under favourable conditions e.g. Chlamydomonas.
In Vaucheria, compound zoospores called synzoospore are formed.

2) Aplanospores : these are non motile thin walled zoospores , formed by cleavage of protoplasts within a cell. They are formed under unfavourable conditions e.g. Ulothrix

3) Akinetes : these are formed under unfavourable conditions as method of perinnation. They are thick walled and non motile. On release they form new thalli e.g. Anabaena

4) Hypnospores: these are thick walled aplanospores and are formed during unfavourable conditions. Under prolonged unfavourable conditions the protoplasm of Hypnospores divides to make cysts e.g. Chlamydomonas nivalis.

5) Tetraspores : these are haploid thin walled non motile spores formed after reduction division in diploid tetrasporangia e.g. members of Rhodophyceae and Phaeophceae.

6) Autospores : these are similar to the parent cell. In Chlorella and Scenedesmus autospores acquire all characteristics of parent cells before their discharge from sporangium.

Diatoms are the main producers in marine environment. So, they are also known as the 'pearls of ocean'. As walls of diatoms are made of silica, they do left behind a large amount of cell deposits in their habitat. This accumulation is called diatomaceous earth. Diatomaceous earth is gritty in nature and hence is used for polishing and, in filtration of oils and syrups.

Kingdom Monera includes living organisms that are single celled, such as bacteria. They neither have a nucleus nor cell membrane. The organisms that are included in this kingdom are prokaryotes. Kingdom Monera is divided into two groups i.e. archaebacteria and eubacteria.

A flower in which both, male and female reproductive organs are absent is called a neuter flower. E.g. Ray florets of a sunflower plant. · A flower in which both, male and female reproductive organs are absent is called a neuter flower. Sunflower uses a method of cross-pollination for reproduction by attracting insects like bees and they spread the reproductive pollen from one flower to another flower. The ray florets of sunflower are often called as a neuter flower as it does not male or female parts.

• Mitosis results in the production of diploid daughter cells with identical genetic complement usually.
• Cell divides by mitosis to restore the nucleo-cytoplasmic ratio.
• Helps in cell repair.
• Mitotic divisions in the meristematic tissues result in a continuous growth of plants throughout their life.

Cytokines are a group of proteins secreted by cells of the immune system that act as chemical messengers. Cytokines released from one cell affect the actions of other cells by binding to receptors on their surface. Through this process, cytokines help regulate the immune response. They act through receptors, and are especially important in the immune system; cytokines modulate the balance between humoral and cell-based immune responses, and they regulate the maturation, growth, and responsiveness of particular cell populations.

Bivalent: Complex formed by a pair of synapsed homologous chromosomes is called a bivalent. It is also known as a tetrad.

The production of three types of flowers namely staminate flowers, pistillate flowers and bisexual flowers in the same plant is known as polygamous. E.g. Musa.

• Calyx-
• The calyx is the outermost whorl of the flower and the members are called
• The calyx may be gamosepalous , when sepals are united or polysepalous when sepals are free.

Pinacocytes, which are epithelial-like cells, form the outermost layer of sponges and enclose a jelly-like substance called mesohyl. Mesohyl is an extracellular matrix consisting of a collagen-like gel with suspended cells that perform various functions.

A N S W E R
Pteridophyte are also called as vascular cryptogams. They show the first vascular property in the plant kingdom. Vascular plants are those plants, who have xylem and phloem.

Sometimes in C₃ plants, RuBisCO binds to oxygen molecules and the reaction deviates from the regular metabolic pathway. The combination of RuBP and oxygen molecules leads to the formation of one molecule of phosphoglycerate and phosphoglycolate. This pathway is called photorespiration. During photorespiration, no sugar or ATP molecules are synthesized, but just CO₂ is released at the expense of ATP and the whole process is futile.

However, C₄ plants do not undergo photorespiration due to their special mechanism to increase the CO₂ level for enzyme binding. During the Hatch and Slack Pathway, the C₄ acid, oxaloacetic acid (OAA) breaks down to release CO₂. This ensures the high concentration of intercellular CO₂. Thus, in C₄ plants, RuBisCO is more active as a carboxylase enzyme rather than as oxygenase. This is why C₄ plants have better productivity.

Mitochondria synthesize energy-rich molecules that is ATP. They are so-called because they carry out the process of aerobic respiration and generate the energy molecules (ATP or Adenosine Triphosphate) for cell operation. Therefore they are known as the powerhouse of the cell.

Another important organ system is the circulatory system. The earthworm has a closed circulatory system. An earthworm circulates blood exclusively through vessels. There are three main vessels that supply the blood to organs within the earthworm. These vessels are the aortic arches, dorsal blood vessels, and ventral blood vessels. The aortic arches function like a human heart. There are five pairs of aortic arches, which have the responsibility of pumping blood into the dorsal and ventral blood vessels. The dorsal blood vessels are responsible for carrying blood to the front of the earthworm’s body. The ventral blood vessels are responsible for carrying blood to the back of the earthworm’s body.

The members of Phaeophyceae or brown algae possess chlorophyll a, chlorophyll c, carotenoids and xanthophyll. They vary in colour depending upon the amount of the xanthophyll pigment, fucoxanthin present in them

The respiratory zone includes the structures of the lung that are directly involved in gas exchange: the terminal bronchioles and alveoli. ... This is a blood-air barrier through which gas exchange occurs by simple diffusion. In the mediastinum, at the level of the fifth thoracic vertebra, the trachea divides into the right and left primary bronchi. The bronchi branch into smaller and smaller passageways until they terminate in tiny air sacs called alveoli.

The coralloid roots of Cycas are symbiotically associated with nitrogen fixing blue-green algae, Anabaena cycadae and Nostoc punctiforme. In the middle cortex of coralloid roots, there occurs a broad blue green zone, which is known as algal zone. Coralloid roots are irregular, negatively geotropic, dichotomously branched coral like roots which do not possess root hair and root caps.

Red algae are different from other groups except for diatoms. Listed below are general characteristics of Red Algae.

• Lack of flagella and centrioles
• Presence of photosynthetic pigments
• Found both in marine and freshwater
• They show biphasic or triphasic life cycle patterns.
• They are a multicellular, filament, blade structure.
• Stored food is in the form of starch and polymers of galactan sulphate
• A pit connection (hole in the septum) is formed between two algal cells.
• Have a diffuse growth pattern- Apical growth, Complex oogamy (triphasic)
• These group of red algae is generally found in tropical marine locations
• The mode of nutrition may either be saprophytic, parasitic or also epiphytic.