Mammals use negative pressure to suck air in. The diaphragm contracts and move down, the intercostal muscles contract and move up and out. This causes the lungs to expand. The pressure inside the lungs drops.

If meristematic cells cease to divide, the growth of the plant will be hindered and will undergo a period of dormancy depending upon the seasonal changes in the climate.

Oligomycin B and DCCD inhibit oxidative phosphorylation by blocking the proton pore of the ATP synthase.

In z - scheme, PSII is excited first and releases an electron. This electron is accepted by an e− acceptor, plastoquinone and passed to the electron transport system (ETS) and then to plastocyanin which transfers electrons to PSI.

Meiosis is essential in sexually reproducing organisms because it keeps the chromosomes number constant.

Mitosis cannot occur without DNA replication in S-phase because the trigger for mitosis takes place due to the disturbance in nucleocytoplasmic ratio caused by DNA replication in S-phase.

Calculation of number of mitosis
Mitosis of one cell produces 2 cells. Similarly, 2 cells undergoing mitosis give rise to 4 cells and so on.
This can be generalised as:
2ⁿ = number of daughter cells, where n = number of cycles of mitotic cell division.
Since the tissue has 1024 cells
⇒ 1024 = 210 cycles
Hence, the original parental single cell has undergone 10 cycles of mitosis to give rise to 1024 cells.
Ten cycles of mitosis.

Interphase (more specifically, G1 phase of interphase). Q. It is said that the one cycle of cell division in human cells (eukaryotic cells) takes 24 hours.

The sticky layer of cell envelope is called glycocalyx. It is also known as mucilage sheath.

Ootheca is produced by clitellum. Mature sperms, eggs and nutritive fluid are deposited in it.

The earthworms make burrows in the soil of playground. This spoils the ground.

The matrix of the bone is through and contains a protein called ossein which makes it hard . It has mineral deposits of calcium and phisphates

Glandular epithelium, also known as glandular tissue, refers to a type of epithelial tissue involved in the production and release of different secretory products, such as sweat, saliva, breast milk, digestive enzymes, and hormones, among many other substances.

In grasses, certain adaxial epidermal cells along the veins modify themselves into large empty, colourless cells called bulliform cells. These cells are responsible for the curling of leaf surfaces in grass.

The dark colour is due to the accumulation of secondary metabolities like tannins, gums, oils and resins, etc.,in the wood tissue. 

The empty space in pneumatic bones helps in weight reduction of skeleton in birds.It is a kind of flight adaptation in birds

In tapeworms, body is divided into number of segments called proglottids that are budded off from the neck Each segment is able to perform all the vital function of body. This type of segmentation is called pseudo metamerism or pseudo segmentation.

Frog and birds.

Pollination(by wind) in Gymnosperms is direct, as stigma is absent. the pollen grain reach the micropylar ends of ovules directly.

Seeds in gymnosperms remain exposed over the surface of the megasporophylls.This is because megasporophylls are not folded to form pistils like in angiosperms.

Classification of organisms into plants and animals was easily done and was easy to understand.

A virus cannot grow on non-living culture medium because it needs living cells for its metabolism and multiplication.

Lichens are dual organisms which contain a fungus or mycobiont and an alga or phycobinot.

The spectrum of diversity in the living world can be known only through the study of taxonomy.