The fossa ovalis is a depression in the right atrium of the heart, at the level of the interatrial septum, the wall between right and left atrium. The fossa ovalis is the remnant of a thin fibrous sheet that covered the foramen ovale during fetal development.

Cells are similar to factories with different labourers and departments that work towards a common objective. Various types of cells perform different functions. Based on cellular structure, there are two types of cells:

Prokaryotes
 

1. Prokaryotic cells have no nucleus. Instead, some prokaryotes such as bacteria have a region within the cell where the genetic material is freely suspended. This region is called the nucleoid.
2. They all are single-celled microorganisms. Examples include archaea, bacteria, and cyanobacteria.
3. The cell size ranges from 0.1 to 0.5 µm in diameter.
4. The hereditary material can either be DNA or RNA.
5. Prokaryotes reproduce by binary fission, a form of sexual reproduction.

Eukaryotes

1. Eukaryotic cells are characterised by a true nucleus.
2. The size of the cells ranges between 10–100 µm in diameter.
3. This broad category involves plants, fungi, protozoans, and animals.
4. The plasma membrane is responsible for monitoring the transport of nutrients and electrolytes in and out of the cells. It is also responsible for cell to cell communication.
5. They reproduce sexually as well as asexually.
6. There are some contrasting features between plant and animal cells. For eg., the plant cell contains chloroplast, central vacuoles, and other plastids, whereas the animal cells do not.

Cartilage is a thin, fibrous, flexible connective tissue, which is mainly found in the external ear, larynx, respiratory tract, and the articulating surface of the joints. These cartilages lack blood vessels; therefore, the growth and development of these tissues are slower compared to that of other tissues. Altogether, there are three different types of cartilages, namely:

1. Hyaline cartilage: It serves as a shock absorber and allows the smooth movement of the bones at joints. They are mainly found in the nose, respiratory tract, and joints
2. Fibrocartilage is found in the knee, and it is tough and inflexible.
3. Elastic cartilage is found in-ear, epiglottis, and larynx. It is the most flexible cartilage.

The three major differences between chordates and non- chordates are:

i. Notochord: is Present at some stage or replaced by a backbone made of ring like vertebrae in chordates while in non-chordates notochord or backbone is absent.

ii. Nerve cord:  Single, dorsal, without ganglia in chordates, and Double, ventral, usually bearing ganglia in non-chordates

iii. Pharyngeal gill slits: are present in chordates and absent in non-chordates.

Meiosis is a process where a single cell divides twice to produce four cells containing half the original amount of genetic information. These cells are our *** cells – sperm in males, eggs in females. During meiosis one cell divides twice to form four daughter cells. In each of these phases, there is a prophase, a metaphase, and anaphase and a telophase. In meiosis I these are known as prophase I, metaphase I, anaphase I and telophase I, while in meiosis II they are known as prophase II, metaphase II, anaphase II and telophase II.

The word glycolysis is of Greek origin, where 'glykos' means sweet, and 'lysis' means splitting. ... Hence, Glycolysis literally means "sugar splitting" or "sugar breaking"; this accurately describes the process of glycolysis, in which a 6-carbon sugar molecule is broken down into two 3-carbon molecules. The main purpose of glycolysis is to provide pyruvate for the trichloroacetic acid (TCA) cycle, not to make adenosine 5′-triphosphate. The glycolytic production of pyruvate reduces the cytosol by increasing the ratio of NADH [a reduced form of NAD+ (nicotinamide adenine dinucleotide)] to NAD+.

An amino acid is an organic molecule that is made up of a basic amino group (−NH2), an acidic carboxyl group (−COOH), and an organic R group (or side chain) that is unique to each amino acid. There are basically three major classifications for amino acids (1) those with nonpolar R group, (2) those with uncharged polar R groups, and (3) those with charged polar R group. The table below shows us all 20 amino acids with their codes.

Basidiomycota are filamentous fungi composed of hyphae (except for basidiomycota-yeast; refer yeast for more information) and reproduce sexually via the formation of specialized club-shaped end cells called basidia that normally bear external meiospores(usually four). These specialized spores are called basidiospores. However, some Basidiomycota reproduce asexually in addition or exclusively. Basidiomycota that reproduce asexually (discussed below) can be recognized as members of this division by gross similarity to others, by the formation of a distinctive anatomical feature (the clamp connection - see below), cell wall components, and definitively by phylogeneticmolecular analysis of DNA sequence data.

Chromosome duplication is essential so that each daughter cell receives equal number of chromosomes from the parent cell. Hence, it is vital to generate an exact copy of the parent cell. The S phase of a cell cycle occurs during interphase, before mitosis or meiosis, and is responsible for the synthesis or replication of DNA. In this way, the genetic material of a cell is doubled before it enters mitosis or meiosis, allowing there to be enough DNA to be split into daughter cells.

Elements as a species of atoms that have the same number of protons in their atomic nuclei.
The elements are arranged in the periodic table and are split depending upon their groups as either metallic or non-metallic. Metallic is further classified into Main Group Metals, Transition Metals, and f-block metals. These are again further divided, depending upon their properties.

Cockroach belongs to phylum Arthropoda. The body of cockroach has three segments known as head, thorax and abdomen. The female reproductive system of cockroach consists of two large ovaries. The ovaries lie laterally in the 12 th and 13 th segments. Each ovary is formed of a group of eight ovarian tubules or ovarioles. They contain a chain of developing ova. Oviducts from each ovary unite into a single median oviduct.

The vital capacity is the total volume of air that can be expired after a maximum inhalation or maximum air that a person can breathe in after forced expiration. It is an important measure of a person's respiratory health.

Renal abscess is treated with antibiotics given through the blood by IV (“intravenously”) and/or by draining the pus from the abscess. The draining can be done with surgery or by putting a tube (“catheter”) through a needle in the skin over the kidney (“percutaneous drainage”). If your kidneys stop working completely, your body fills with extra water and waste products. This condition is called uremia. Your hands or feet may swell. You will feel tired and weak because your body needs clean blood to function properly.

Crossing over occurs between prophase I and metaphase I and is the process where two homologous non-sister chromatids pair up with each other and exchange different segments of genetic material to form two recombinant chromosome sister chromatids. Crossing over (recombination) occurs during pachytene. Recombination involves mutual exchange of the corresponding segments of non-sister chromatids of homologous chromosomes and produces variations. It takes place by breakage and reunion of chromatid segments.

Crossing over occurs between prophase I and metaphase I and is the process where two homologous non-sister chromatids pair up with each other and exchange different segments of genetic material to form two recombinant chromosome sister chromatids. Crossing over (recombination) occurs during pachytene. Recombination involves mutual exchange of the corresponding segments of non-sister chromatids of homologous chromosomes and produces variations. It takes place by breakage and reunion of chromatid segments.

Phycocolloids are nothing but the covering on the body of the algae and other microbes which prevents them from drying or freezing in the extreme environment in water, it is basically a protective layer.
There are mainly three types of the same. For example, alginic (algin) acid, fucoidin and fucin.

Enzymes can be defined as biological polymers that catalyze biochemical reactions.
Enzymes are a linear chain of amino acids, which give rise to a three-dimensional structure. The sequence of amino acids specifies the structure, which in turn identifies the catalytic activity of the enzyme. Upon heating, enzyme’s structure denatures, resulting in a loss of enzyme activity, that typically is associated with temperature.

Brassicaceae or mustard family is an economically important family of flowering plants. In Brassicaceae, the stamens are 6 which are arranged in two whorls. The outer two stamens are short and inner four stamens are long, tetradynamous (4 inner stamens are longer than 2 outer stamens), polyandrous (all the stamens are free), anthers dithecous, basifixed, introrse.

So, the correct answer is 'Brassicaceae'.

• G1 phase (Gap 1) – G1 phase is the phase of the cell between mitosis and initiation of replication of the genetic material of the cell. During this phase, the cell is metabolically active and continues to grow without replicating its DNA.

• S phase (Synthesis) – DNA replication takes place during this phase. If the initial quantity of DNA in the cell is denoted as <i>2N</i>, then after replication it becomes <i>4N</i>. However the number of chromosomes does not vary, viz., if the number of chromosomes during G1 phase was <i>2n</i>, it will remain <i>2n</i> at the end of S phase. The centriole also divides into two centriole pairs in the cells which contain centriole.

• G2­ phase (Gap 2) –During this phase, the RNA, proteins, other macromolecules required for multiplication of cell organelles, spindle formation, and cell growth are produced as the cell prepares to go into the mitotic phase.

• M phase

  This is the mitotic phase or the phase of the equational division as the cell undergoes a complete reorganization to give birth to a progeny that has the same number of chromosomes as the parent cell. The other organelles are also divided equally by the process of cytokinesis which is preceded by mitotic nuclear division. The mitotic phase is divided into four overlapping stages:-

• Prophase,
• Metaphase,
• Anaphase, and
• Telophase

 Active transport is the movement of molecules across a membrane from a region of lower concentration to a region of higher concentration against the concentration gradient, often assisted by enzymes and requires energy 

 Passive transport is the movement of ions and molecules across the cell membrane without requiring energy. 

The fluid mosaic model was proposed by S.J. Singer and Garth L. Nicolson. This model explains the structure of the plasma membrane of animal cells as a mosaic of components such as phospholipids, proteins, cholesterol, and carbohydrates. These components give a fluid character to the membranes.

Each phospholipid has a hydrophilic head pointing outside and a hydrophobic tail forming the inside of the bilayer.

Cholesterol and proteins are embedded in the bilayer that gives the membrane a mosaic look. Each component has a specific function to perform.

Inclusion bodies are the non-living structures present in cytoplasm not bounded by, the membrane system. They may either lie free in cytoplasm or may be covered by 2-4 nm-thick, non-protein membrane, e.g., Vacuoles, sulphur granules, etc.

The marine animals termed echinoderms belonging to Phylum Echinodermata of Kingdom Animalia have spiny bodies. 

Characteristics of Echinodermata:

(i) Simple animals may be a star like, spherical or elongate.

(ii) Body triploblastic, coelomate, unsegmented and radially symmetrical.

(iii) Body lacks head but has oral and aboral surfaces. Oral surface of the body has five radial areas called ambulacra.

(iv) Body wall is covered with spiny hard calcareous (calcium carbonate) plates (ossicles) that forms a rigid or flexible endoskeleton.

Example: Echinus (sea urchin) and Asterias (star fish).

These classifications have a number of advantages. Following are the advantages of classifying organisms:

• It makes us aware of and gives us information regarding the diversity of plants and animals.
• It makes the study of different kinds of organisms much easier.
• It tells us about the inter-relationship among the various organisms.
• It helps to understand the evolution of organisms.
• It helps environmentalists to develop new methods of conservation of plants and animals.