• Indented key-It is also called as yoked key is most commonly used in the filed of taxonomic study.
• It is capable of giving visual effect of a particular group.
• In case of indented key, the choice of couplet must maintain equal distance from left margin.
• Bracketed key-In this case, numbering system must be present in choice of couplet.
• The choices can be easily separated and this is most helpful if previous couplet is there.

Mesosomes or chondrioids are folded invaginations in the plasma membrane of bacteria that are produced by the chemical fixation techniques used to prepare samples for electron microscopy.

These structures are invaginations of the plasma membrane observed in gram-positive bacteria that have been chemically fixed to prepare them for electron microscopy. They were first observed in 1953 by George B. Chapman and James Hillier, who referred to them as "peripheral bodies." They were termed "mesosomes" by J. D. Robertson in 1959.

Most microbiologists will argue that mesosomes do not exist. They are likely an artifact of the preparation process for electron microscopy since they cannot be observed in "non-fixed" samples.

However, as their existence is debatable, those who believe in their existence state that they are the infoldings in the plasma membrane, they are rich in enzymes that helps to perform functions like cellular respiration, DNA replication, secretion of glycocalyx and cell division (most important function; it increases the surface area of the cell membrane.)

Cells are the basic building blocks of all living things. The human body is composed of trillions of cells. They provide structure for the body, take in nutrients from food, convert those nutrients into energy, and carry out specialized functions.

Cells also contain the body’s hereditary material and can make copies of themselves. Cells have many parts, each with a different function. Some of these parts, called organelles, are specialized structures that perform certain tasks within the cell.

1. Within a plant, apoplast is the space lying outside the plasma membrane consisting of intercellular spaces along with cell wall.

2. The major part of water & ions are transported by apoplastic pathway in the root cortex as cortical cells are packed loosely and offers low resistance to the flow of water.

3. The apoplastic route is blocked by a Casparian strip of endodermal cells. Hence, the symplastic route is utilized to deliver water and ion over cortex.

4. Since apoplast is made up of non-living components, the apoplastic route is least affected by the metabolic state of the root.

Within a plant, the apoplast is the space outside the plasma membrane within which material can diffuse freely. It is interrupted by the Casparian strip in roots, by air spaces between plant cells and by the plant cuticle.

Bacteria is a prokaryotic, unicellular organism having cell wall made up of glcoprotein with or without flagella.

Diseases caused by fungi are usually on the skin, lung, mouth and ****** tract etc that can easily be reached by things in the environment.

A notochord is a primitive beginning to the backbone. It appears in embryos as a small flexible rod made from cells from the mesoderm, which is one of the three layers of cells of embryos.

On the Basis of Absence and Presence of Notochord:

 The notochord in majority of chordates is subsequently replaced by vertebral columns, which are known as vertebrates. In the case of small number of chordates, the notochord is not being replaced by vertebral column rather notochord remains as a notochord, and they are regarded as protochordates. But in non-cordates, notochord and vertebral column both are absent.

Housefly

Mango

Wheat

The phylum Chordata contains all of the animals that have a rod-like structure used to give them support.

In most cases this is the spine or backbone. Within Chordata there are five classes of animals: fish, amphibians, reptiles, birds, and mammals

1. there is a hiererchy that follows; 

kingdom

phylum[animals]/division[plants]

class

order

family

genus

species

2. just write all the scientific names with their common names and read them as much as you can, everytime. i bet you will not forget all your life. thats the only way to learn them.

Plants and animals both grow by mitotic divisions but their growth has certain differences:

• The plants can grow throughout their lifetime, which may be very short for annuals or very long for perennials. Animals grow for a certain period of time till they attain sexual maturity. After being sexually mature they stop growing in size.
• In perennial plants, there may be alternating periods of vegetative and reproductive growth.
• Plants have a high power of regeneration while higher animals lack this. True regeneration power is seen only in lower animals like planaria or echinnoderms. Among higher animals only some have the power of regeneration and that too of partial regeneration.
• For example, lizard can grow its tail back when amputated but not any other body part.
• In animals growth is diffused, that is growth divisions occur throughout the body, while in plants growth is restricted to localised areas called meristems where the growth divisions occur.
• Plant cells are pluripotent that they can develop into all other type of plant cells, but in animals this power is limited to the stem cells only.

Solution: Pteridophyta plants are consider as 1st terrestrial plant because it can survive on land as well as in water.

Some part of their life cycle is aquatic and half is terrestrial

The defining properties of living organisms are-

1. Nutrition- Taking in nutrients which are organic substances and mineral ions, containing raw materials and energy for growth and tissue repair, absorbing and assimilating them.
2. Excretion-Removal from organisms of toxic materials, the waste products of metabolism
3. Respiration-Chemical reactions that break down nutrient molecules in living cells to release energy.
4. Reproduction-Progresses that make more of the same kind of organism.
5. Growth-The permanent increase in size and dry mass by an increase in number of cells, cell size, or both.
6. Movement-An action by an organism or part of an organism that changes position or place. 

But growth and movement cannot be taken as defining property because there are certain living things which do not show these properties. For example, infertile couples cannot reproduce yet they are living.

Spleen always get oxygenated blood as it is connected to heart through portal vein.

• Renin is an enzyme that is involved in the regulation of arterial blood pressure.
• Rennin AKA Chymosin, is an endopeptidase produced by some animals to curdle the milk they digest.