Question

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Answer 1

• 7)draw a neat labelled diagram of typical structure of flower
• attached

• 8)geographical isolation be a major factor in the speciation of a self pollinating plant species why or why not
• No, geographical isolation will not be a major factor in the speciation of self-pollinating plant species. Geographical isolation creates the separation of the population. It is because in self-pollinating species, new variants are not formed and they do not show any variation in the population.

• 9)What are the differences between the transport of materials in xylem and phloem
• Xylem tissue helps in the transport of water and minerals. Phloem tissue helps in the transport of food. Water is transported upwards from roots to all other plant parts. ... Transport of food in phloem requires energy in the form of ATP.

• 10)why is it necessary to separate oxygenated andkis oxygenatedblood in mammals and birds
• Answer: In birds and mammals have a double circulation system where both the oxygenated and deoxygenated blood maintains separate. ... It is necessary for them to separate oxygenated and de-oxygenated blood so that their circulatory system is more efficient and can maintain their constant body temperature.

• draw a neat labelled diagram of human excretory system
• picture attached

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Answer 2

Answer:

$\huge\mathbb\color{green}{Answer}$

$\rm{\fbox{what \: is \: a \: self \: pollination ? }}$

→ Answer:- Self-pollination is one that occurs either within the same flower or between two flowers on the same plant.

→ The pollen grains from the anthers may fall on the stigma of the same flower or the stigma of another flower on the same plant.

$\rm{\fbox{what \: is \: cross \: pollination ?}}$

→ This occurs between two flowers on different plants of the same species.

$\rm{\fbox{agents \: of \: cross \: pollination}}$

→ For cross pollination to take place, an agent has to be available. These agents can be insects, wind or water.

$\rm{\fcolorbox{aqua}{aqua}{Insects}}$

→ When insects help in pollination, such as transfer of pollen grains is called insect pollination.

Characteristics of insect-pollinated flower

→ These flowers are large with coloured petals, to attract insects.

→ These are scented so that insect locate the flowers by smell.

→ These contain nectar as food for insects.

→ These produce sticky pollen grains so that they may stick to the body parts of the insect.

$\rm{\fcolorbox{aqua}{aqua}{wind}}$

→ When wind is the agent of cross pollination, it is called wind pollination.

→ Example:- Maize, palm, pine, etc.,

Characteristics of wind-pollinated flowers:-

→ They are usually small and are of dull colours.

→ They generally have a long anthers protruding out of the flower so that the pollen grains may get blown off easily.

→ They produce a large quantity of pollen.

→ The pollen grains are light so that they easily carried away

$\rm{\fcolorbox{aqua}{aqua}{water}}$

→ Pollination where water acts as an agent of cross pollination is known as water pollination.

→ Example:- Vallisneria

Characteristics of water-pollinated flowers:-

→ Flowers are small and light so that they can easily float on water.

→ Male and female flowers are borne on seperate plants.

→ Pollen grains are produced in large numbers

Question 9↓

$\rm{\fbox{xylem}}$

→ Conducts water and mineral salts from the roots to the aerial parts of the plant.

→ Made up of tracheids, vessels, xylem parenchyma and xylem fibres.

→ Conducting cells (vessels and tracheids) are dead.

→ Conduction is unidirectional

→ Conduction does not require any expenditure of energy.

$\rm{\fbox{phloem}}$

→ Translocates food from the leaves to the storage organs and growing parts of the plant.

→ Made up of sieve tubes, companion cells, phloem parenchyma and phloem fibres.

→ Conducting cells (sieve tubes) are living

→ Conduction is bidirectional

→ Conduction requires expenditure of energy.

10) Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?

• Answer:-In birds and mammals have a double circulation system where both the oxygenated and deoxygenated blood maintains separate.
• Warm-blooded animals such as birds and mammals maintain constant body temperature by cooling themselves when they are in a hotter environment and by warming their bodies when they are in a cooler environment.
• Hence, these animals require more oxygen (O2) for more cellular respiration so that they can produce more energy to maintain their body temperature.
• It is necessary for them to separate oxygenated and de-oxygenated blood so that their circulatory system is more efficient and can maintain their constant body temperature.
• It is also better if the oxygenated blood stays separate, as its combination with deoxygenated blood will impure the entire blood.