Structural Organisation Of Animals And Plants

Answer (d) Respiratory pigment

The epithelia rest on a thin, non-cellular basement membrane. The epithelia generally lack blood vessels, but still have a good power of repair after injury

Answer (d) Volkmann's canal

Step 1: Understanding the structural organization.
The correct organization in animals starts at the cellular level, where cells group together to form tissues. Tissues then form organs, which in turn make up organ systems.
Step 2: Analyzing the options.
(A) Tissues → Organs → Systems → Cells: Incorrect. This option presents the organization in the wrong order.
(B) Cells → Tissues → Organs → Systems: Correct. This is the proper hierarchy of biological organization in animals.
(C) Cells → Organs → Systems → Tissues: Incorrect. This sequence is not correct, as tissues precede organs.
(D) Systems → Organs → Cells → Tissues: Incorrect. This sequence is entirely incorrect as it does not follow the biological hierarchy.
Step 3: Conclusion.
The correct answer is (B) Cells → Tissues → Organs → Systems.

Step 1: Understanding the white adipose tissue.
White adipose tissue is primarily made up of adipocytes (fat cells), which contain large lipid droplets. These cells reflect light and make the tissue appear opaque.
Step 2: Analyzing the options.
(A) large amount of intra-cellular protein: Incorrect, adipose tissue is characterized by fat storage, not by large amounts of protein.
(B) large amount of extra-cellular fat: Incorrect, the fat in adipose tissue is intracellular, not extracellular.
(C) large number of adipocytes: Correct, the large number of fat cells makes the tissue appear opaque.
(D) more number of white fibres: Incorrect, white fibers are not the primary contributors to the opacity of adipose tissue.
Step 3: Conclusion.
The correct answer is (C) large number of adipocytes, as adipocytes give the tissue its characteristic opacity.

Anthers in Angiosperms:

In angiosperms (flowering plants), the anthers are the male reproductive structures responsible for producing and containing the pollen grains. The anthers are an essential part of the flower's stamen, which is the male reproductive organ. The stamen is made up of two main parts: the anther and the filament. The anther is typically located at the top of a slender stalk called the filament, which helps position the anther for effective pollen dispersal.

Structure of the Anther:
The anthers are typically composed of two lobes, each called a microsporangium. These lobes contain microsporocytes (also known as pollen mother cells), which undergo meiosis to produce microspores. The microspores are haploid cells that develop into the male gametophyte, commonly known as the pollen grain. The pollen grain contains the male gametes (sperm cells) that will fertilize the female ovule during reproduction.

Variations Among Species:
The shape, size, and number of anthers can vary significantly among different species of angiosperms. For example, some flowers have only one anther, while others may have multiple anthers fused together to form a ring or other configurations. This variation plays a role in the mechanisms of pollination and can influence how efficiently pollen is transferred from the anther to the stigma, the female reproductive organ.

Conclusion:
The anther plays a crucial role in the reproductive process of angiosperms by producing and dispersing pollen grains, which carry the male gametes to fertilize the ovules. Its structure and number can vary between species, reflecting the diversity of reproductive strategies in flowering plants.