(a) When a seed of an orange is squeezed, many embryos, instead of one are observed. Explain how it is possible.
(b) Are these embryos genetically similar or different ? Comment.
(a) It is due to polyembryony. Occurrence of more than one embryos in a seed is called as POLYEMBRYONY. In orange, the nucellar cells, synergid or integument cells develops into a number of embryos of different sizes. eg : - Citrus.
(b) In such embryos parental characters are maintained hence they are genetically similar. In this process, there is no segregation of characters in the offspring (progeny).
Fill in the blanks:
(a) Humans reproduce __________. (asexually/sexually)
(b) Humans are__________. (oviparous/viviparous/ovoviviparous)
(c) Fertilization is __________ in humans. (external/internal)
(d) Male and female gametes are __________. (diploid/haploid)
(e) Zygote is __________. (diploid/haploid)
(f) The process of release of the ovum from a mature follicle is called__________.
(g) Ovulation is induced by a hormone called the __________.
(h) The fusion of male and female gametes is called _____________.
(i) Fertilisation takes place in _____________.
(j) Zygote divides to form _____________which is implanted in uterus.
(k) The structure which provides vascular connection between fetus and uterus is called ____________.