Secondary succession takes place on/in
bara rock
degraded forest
newly created pond
newly created pond
B.
degraded forest
Secondary succession takes place on degraded forest. It is the process of regrowth of an ecosystem which undergoes a destructive event such as fire, avalanche, agricultural clearing, deforestation or disease. The rate of succession and establishment of communities is faster as compared to growth in primary succession.
Capacitation refers to changes in the
Sperm before fertilization
Ovum before fertilization
Ovum after fertilization
Ovum after fertilization
Which of the following represents the correct combination without any exception?
Characteristic | Class |
Mammary gland; hair on body; pinnae; two pairs of Limbs | Mammalia |
Characteristic | Class |
Mouth ventral, gills without operculum; skin with placoid scales; persistent notochord | Chondricht hyes |
Characteristic | Class |
Sucking and circular mouth; jaws absent, integument without scales; paired appendages | Cyclostomata |
Characteristic | Class |
Sucking and circular mouth; jaws absent, integument without scales; paired appendages | Cyclostomata |
Which of the following viruses is not transferred through semen of an infected male?
Hepatitis B virus
Human immunodeficiency virus
Chikungunya virus
Chikungunya virus
The mass of living material at a tropic level at a particular time is called
gross primary productivity
standing state
net primary productivity
net primary productivity
Which of these is not an important component of initiation of parturition in humans?
Increase in oestrogen and progesterone ratio
Synthesis of prostaglandins
Release of oxytocin
Release of oxytocin
In an ecosystem the rate of production of organic matter during photosynthesis is termed as
net primary productivity
gross primary productivity
secondary productivity
secondary productivity
Select the correct option:
Column I | Column II | |
A | Synapsis aligns homologous chromosomes | 1. Anaphase-II |
B | Synthesis of RNA and protein | 2. Zygotene |
C | Action of enzyme recombinase | 3. G2-phase |
D | Centromeres do not separate but chromatids move towards opposite poles | 4. Anaphase-I |
5. Pachytene |
Which of the following cells during gametogenesis is normally dipoid?
Primary polar body
Spermatid
Spermatogonia
Spermatogonia