Bacteria: 

These are single-celled microorganisms that play a crucial role in decomposition. They are very efficient at breaking down complex organic molecules, such as proteins, fats, and carbohydrates.

Fungi: 

These are multicellular organisms that also play an important role in decomposition. They secrete enzymes that break down organic matter, and then absorb the resulting nutrients.

Worms: 

Certain types of worms, such as earthworms, are also decomposers. They eat dead plant and animal matter and break it down into smaller pieces, which are then further broken down by bacteria and fungi.

Insects: 

Many insects, such as beetles, flies, and maggots, also play a role in decomposition. They consume dead organic matter and help to break it down into smaller pieces.

Other organisms: 

Other organisms, such as snails, slugs, and some types of bacteria, also play a role in decomposition by consuming dead organic matter.

All of these decomposers work together to break down dead organic matter and recycle nutrients back into the ecosystem. Without them, organic matter would accumulate and nutrients would be locked up, leading to a less productive and less diverse ecosystem.

In the 1860s, Mendel conducted a series of experiments on pea plants in which he observed the transmission of traits from one generation to the next. He discovered that traits are inherited in a predictable pattern and proposed the laws of inheritance, which are now known as Mendelian genetics.

Mendel's work went largely unnoticed for several decades, but it was rediscovered in the early 20th century by several scientists who were working on similar problems. These scientists built upon Mendel's work and developed new concepts and tools for studying genetics, including the discovery of the structure of DNA by Watson and Crick in 1953.

Since then, the field of genetics has exploded, and we now have a much better understanding of how genes are passed down from one generation to the next, how they are expressed, and how they interact with the environment. This knowledge has had a profound impact on our understanding of biology, medicine, and evolution, and has led to many important discoveries and innovations.

★ Amazon River: 

The Amazon River in South America is the largest in the world by volume, with a discharge greater than the next seven largest rivers combined. It is also the second-longest river in the world.

★ Nile River: 

The Nile River in Africa is the longest in the world, stretching over 6,650 kilometers (4,132 miles). It is historically and culturally significant to many countries in Africa and the Middle East.

★ Yangtze River: 

The Yangtze River in China is the longest river in Asia and the third-longest in the world. It is a major transportation route and source of hydroelectric power.

★ Mississippi River: 

The Mississippi River in North America is the fourth-longest in the world and is culturally and historically significant to the United States. It is also an important transportation route and source of freshwater.

★ Yenisei River: 

The Yenisei River in Russia is the largest river system flowing into the Arctic Ocean and is the fifth-longest river in the world. It is an important transportation route and source of hydroelectric power.

★ Congo River: 

The Congo River in Africa is the second-largest river in the world by volume and is an important transportation route and source of hydroelectric power.

★ Mekong River: 

The Mekong River in Southeast Asia is the twelfth-longest in the world and is culturally and economically significant to many countries in the region.

★ Danube River: 

The Danube River in Europe is the second-longest river in Europe and an important transportation route.

★ Ganges River: 

The Ganges River in India is culturally and spiritually significant to many people in India and is an important source of freshwater.

★ Indus River: 

The Indus River in Pakistan is historically and culturally significant and is an important source of freshwater for the region.

1. The term "embryo" denotes the juvenile stage of an animal while it is contained in the egg or the maternal body.

2. The processes that are involved in the transformation of the fertilized egg into a new adult individual are called ontogenic development.

3. Only gametes or generative cells go through the process of maturation or meiosis.

4. Historical development of species is called phylogenetic development.

5. Blastogenesis is the development of new individuals using asexual reproduction.

6. The third phase of development is Cleavage.

7. The proliferating cells in the ovaries are called oogonia.

8. Muscles and blood vascular system are made up of mesoderm.

9. The resulting embryo by infolding of the mesoderm and endoderm is called the gastrula.

10. Blastopore becomes the oral opening in Coelenterata.

11. The formation of spermatozoon and ripening of the egg is called gametogenesis.

12. The second phase of development is fertilization.

13. Endoderm forms the alimentary canal and the digestive glands.

14. Cleavage cells are called blastomeres.

15. The fifth phase of development is the phase of organogenesis.

16. In cleavage, the cells are arranged in a hollow spherical body called a blastula.

17. The group of cells that are segregated from the other cells of the embryo to form an organ is called the rudiment of the respective organ.

18. Larva possesses special organs which are absent in adults.

19. Developmental processes may be repeated in an adult during regeneration.

20. Ectoderm always gives rise to the skin epidermis and the nervous system.

21. When single layers of cells called blastoderm give rise to two or more layers of cells, germinal layers are formed.

22. The fourth phase of development is gastrulation.

23. The more general features in the embryo developed earlier than the more special features is the statement of Baer's Law.

24. Biogenetic law is proposed by Muller and Hackel.

25. The groups of animals having a common basic plan of organization are called the phyla of the animal kingdom.

26. The sixth phase of development is the period of growth and histological differentiation.

27. The generation of cellular diversity is called differentiation.

28. Some cells that can form new structures even in adults are called stem cells.

29. The gametes and their precursor cells are collectively called germ cells.

30. Aristotle supported the idea of epigenesis, which states that the organs of the embryo are formed de novo at each generation.

31. The organs are already present within the egg or sperm in miniature form is the theory of preformation.

32. In Deuterostomia, the blastopore develops into the anus.

33. Biogenetic law states that ontogeny is a shortened and modified recapitulation of the phylogeny.

34. The parts of the alimentary canal lined by ectoderm adjoining the mouth are known as the stomodeum.

35. The creation of an ordered form that involves coordinating cell growth, cell migration, and cell death is called morphogenesis.

36. The developmental pathway from germ cell to mature sperm is called spermatogenesis.

37. When sperm stem cells increase by mitosis, this is the proliferative phase.

38. GDNF is a paracrine factor called the Glial cell line-derived neurotrophic factor.

39. The precursors of sperm and oocyte are called Primordial germ cells.

40. The phase in which the round cells called spermatids eject most of their cytoplasm and become streamlined sperm is called spermiogenesis.

41. Gonocytes are true stem cells.

42. Sertoli cells nourish the developing sperm.

43. Type A spermatogonia can generate more than 1000 sperm per second in adult human males.

44. GDNF promotes the division of spermatogonial stem cells.

45. Stem Cell Factor promotes the transition to spermatogenesis.

46. Spermatogonia with high levels of stra8 divide to become type B spermatogonia.

47. Primary spermatocytes undergo meiosis to yield secondary spermatocytes.

48. The haploid cells formed from secondary spermatocytes called spermatids.

49. Acrosomal vesicle of sperm constructed from Golgi apparatus.

50. The acrosome forms a cap that covers the sperm nucleus.

Reference Books:
✨ An introduction to embryology by B.I. Balinsky.
✨ Developmental Biology by Scott F. Gilbert.