Some important points =
1. Unicellular organisms generally reproduce asexually by means of fission etc. Here the parent organism divides
and continues to live as daughter cells. No natural death is observed. Thus, unicellular organisms are said to be immortal.
2.Earthworm is one such organism where copulation and cross fertilization are required for reproduction although it is hermaphrodite (both male and female
sex organs are present in single individual). It is because in earthworm, testes mature earlier than the ovaries
(protandry).
3.Cleptocamus fower open at ers which do not at all. This is an adaptation of plants for self pollination. Advantage of cleistogamy : Cleistogamous flowers produce assured seed-set even in the absence of pollinators. Disadvantage of cleistogamy : Cleistogamous flowers undergo self pollination which reduces the chances of ariation and evolution of genetically superior progeny. It also results in inbreeding depression.
4. Endothecial cells 2n
Tapetal cells Most of the mature tapetal cells are multinucleate and are polyploid.
Cells of sporogenous tissue 2n Cells of microspore tetrads or microspores n
5. Men from which samples A and B were collected may have some dysfunctioning of seminal vesicles and prostate gland respectively.
6. Fat droplets, casein protein, lactose sugar, mineral salts (sodium, calcium, potassium, phosphorus etc.) and vitamins are main constituents of human milk. It is poor in iron content CDRI, Lucknow developed a non-steroidal oral pill
named 'saheli' which has centchroman as its key
component
: 8. (a) Treponema pallidum
(b) Neisseria gonorrhoeae
: 9. Barrier Diaphragm / Condom Cervical cap
IUD Copper-T
Surgical technique Vasectomy / Tubectomy Hormonal administrations Oral pill/Saheli.
10. The act of expelling the full term young one from the
mother's uterus at the end of gestation period is called parturition. The signals for parturition start from the fully
matured foetus and placenta which induce mild uterine contractions called foetal ejection reflex. This leads to
quick release of oxytocin from the maternal pituitary gland. Oxytocin acts on the uterine muscles and causes
stronger uterine contractions, which in turn further
:stimulates secretion of oxytocin. Relaxin increases the flexibility of the pubic symphysis and helps dilate the uterine cervix. Thus both oxytocin and relaxin lead to
: expulsion of the baby out of the uterus through the
: birth canal
11. Natality is the number of babies produced per thousand 6individuals and mortality is the death rate per thousand
individuals. Demographers generally use the terms crude
: birth rate and crude death rate. Crude birth rate is the number of births per thousand persons in the middle of a given year (ie, on July 7). Crude death rate is the number of deaths per thousand persons in the middle of a given year (i.e, on July 7)
