State the cause of accelerated eutrophication.
Accelerated eutrophication:
It is the ageing of a water body due to nutrient enrichment of its water. It can be natural or artificial. Eutrophication takes thousands of years, but due to human activities the process has been accelerated. So, it is called accelerated eutrophication.
Causes of accelerated eutrophication:
1) Release of nutrient-rich sewage and industrial effluents lead to the introduction of nutrients such as nitrogen and phosphorus.
2) Sewage and industrial effluents also lead to increase in temperature and BOD of the water body, causing increased biological activity, thereby leading to algal blooms.
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 ____________.