(a) State five reasons why animals move from place to place.
(b) State one function each of the following structures found in plants:
(i) epidermis
(ii) phloem
(iii) sclerenchyma.
(c) Give two examples each of the following types of organisms:
(i) parasitic plants
(ii) saprophytes.
(d) State two adaptive features of plants which inhabit salt water swamp.
(e) State two factors each which result in
(i) increase
(ii) decrease, in population density.
(f) Mention four ways in which modern agricultural activities may threaten the survival of species.
(g) State three reasons why mitosis is important to living organisms
(h) State three causes of food spoilage.
Explanation
(a) Reasons why animals move from place to place:
(i) To search for food.
(ii) Escape predators.
(iii) Find mates for reproduction.
(iv) To disperse/reduce competition/overcrowding by moving to new locations.
(v) Avoid dangers. (vi) Find new and favourable habitats.
(b) Function of structures found in plant:
(i) Epidermis: For protection of inner cells from injury, infection, prevent excessive loss of water.
(ii) Phloem: Responsible for the transportation of enzymes/hormones; manufactured food.
(iii) Sclerenchyma: Strengthens the stem/provide mechanical support; makes plants flexible.
(c) Examples of organism:
(i) Parasitic plants: Viscum/mistletoe; dodder plant/Cassytha; Cuscuta; phytophisor; peronospora.
(ii) Saprophyta: Bacteria; fungi/Rhizopus; Mucor, Aspergillus; Mushroom/Agaricus.
(d) adaptive features of plants in salt water swamps: -
- Succulent stem/root/store water; to dilute the salt.
- Presence of pneumatophores/breathing roots; for breathing atmosphere air/oxygen.
- Presence of stilt roots; for anchorage.
- Viviparous seedling; to ensure their survival/continuity.
- Some a secrete excess salt into swamps; to maintain balance of body salt.
(e) Factors that: (i) Increase population density:
- Increased birth rate/natality
- immigration, increase a food availability
- low mortality rate.
(ii) Decrease population density:
- Emigration
- diseases
- drought/famine/natural disaster
- high mortality rate
- low natality rate.
(f) Ways modern agricultural activities may threaten the survival of species: -
- Deforestation/commercial farming destroys habitats of species.
- Destruction/loss of natural vegetation/habitat.
- Over hunting of games reduces population of species.
- Improper/Indiscriminate application of chemical/salinizationteutrophication, pesticides destroys species.
- Lack of afforestation practices.
- Inappropriate fishing methods threaten the population of fish.
(g) Reasons why mitosis is important to living organisms: -
- It ensures growth.
- Involved asexual ,reproduction e.g. fission, budding, spore formation.
- Ensures retention of diploid condition. Repair of tissues within organisms.
- Transfer of exact genetic code from parents to offspring.
(h) Causes of food spoilage: -
- Microbial attacks by bacteria or fungi/or saprophytic action.
- Pest attack by beetles, weevils that destroy stored grains.
- Improper storage which results in deterioration and spoilage of stored foods.
- Destruction of stored fruits and meat by some worms, usually larva of flies.
- Delay in transportation due to bad roads.
- Lack of market facilities for the commodity.
- Poor harvesting method/damage to fruits/ vegetables/tubers during harvesting.
- Poor unhygienic handling/processing/exposure to dust.
- Storage in contaminated containers.
- Use of contaminated water to wash food.