(a) List three transmittable characters in: (I) human beings (ii) plants
(b) State three ways in which genetics has contributed to improvement of agriculture.
(c) A homozygous tall parent was crossed with a homozygous short
Explanation
(a)(i) Transmittable characters in Human beings are:
(1) body stature /posture/shape of body
(2) shape of head/nose/ ear
(3) size of nose/head/ear
(4) colour of skin/hair/eye
(5) characteristic of voice/speech
(6) intelligence
(7) height, blood group, baldness
(8) tongue rolling
(9) sickle cell anaemia.
(ii) Transmittable characters in plants are:
(1) height of plant
(2) size of fruit/ weight of fruit/size of leaf
(3) taste of fruit
(4) colour of leaf/flower/fruits/seeds
(5) resistance to environmental factors/diseases/pests/drought
(6) shape of leaf/seed coat or taste/fruit/flower
(7) leaf texture
(8) life span/habit of growth
(b) Contribution of genetics to improvement in Agriculture are:
(i) It has helped to develop high yielding varieties of plants and animals
(ii) development of early maturing varieties
(iii) improvement of quality of yield
(iv) development of disease resistant varieties through hybridisation/cross breeding.
crossing of F1 generation with homozygous short individuals.
(ii) The phenotypic ratio of offspring in F2 generation is 2:2.
(iii) The genotypic ratio of F2 generation is 2: 2
(d) The probability is 50% or ½. This is because
(i) The genotype of the plants is Tt
(ii) The plants therefore produce gametes of two kinds, T and t in equal number.
(iii) The probability that a gamete will contain T gene is 1 out of 2.