RNA is a ribonucleic acid that helps in the synthesis of proteins in our body. This nucleic acid is responsible for the production of new cells in the human body. It is usually obtained from the DNA molecule. RNA resembles the same as that of DNA, the only difference being that it has a single strand unlike the DNA which has two strands and it consists of an only single ribose sugar molecule in it. Hence is the name Ribonucleic acid. RNA is also referred to as an enzyme as it helps in the process of chemical reactions in the body.

ANSWER

Apocarpous ovary: The flowers with apocarpus ovary have more than one carpel. These carpels are free. Eg: lotus and rose flowers.

Syncarpous ovary: The flowers with syncarpous ovary have more than one carpel. However, these carpels are fused. Eg: flowers of tomato and mustard.

An intentional termination of a pregnancy before it reaches full term is called medical termination of pregnancy (MTP). It is an induced abortion.  In India, MTP is legalized but with certain riders, so that people do not misuse it. These riders and restrictions have been put in place so that illegal female feticides can be controlled and monitored. However, in some countries, MTP is still not accepted or legal as there are many religious, ethical and social issues involved.

MTP is mainly done to get rid of unwanted pregnancies that arise out of casual unprotected *** or sometimes even failure of the contraceptives or even unfortunate incidents of rape.

There are also other medical reasons when MTP is performed. When there is an issue in the pregnancy or the developing fetus, which is likely to be fatal for both the other and the fetus, then MTP is done. MTP is generally safe during the first trimester of the pregnancy.

In India, MTP is legal. It is advised when the pregnancy is harmful to both the fetus and the mother. The other conditions when MTP is advised are to get rid of unwanted pregnancies due to casual *** or failure of the contraceptives.

Pollination is processed by the agent which transfers pollen from the pollen sac or anther to the stigma or ovule in the flower. Pollination done by snails is called malacophily. Such type of flowers is called as malacophilous. These flowers achieve pollination only by the help of snails and slugs.

Sea stars are important members of the marine environment and are considered a keystone species. A keystone species preys on animals that have no other natural predators and if they are removed from the environment, their prey will increase in number and may drive out other species. As an echinoderm, a starfish has amazing powers of regeneration. One of his best defenses against predators is his ability to drop off an arm that's grasped in a predator's mouth. Assuming the predator doesn't bite off the arm, the starfish can intentionally separate it from his body to aid his escape.

Like DNA, RNA (ribonucleic acid) is essential for all known forms of life. RNA monomers are also nucleotides. Unlike DNA, RNA in biological cells is predominantly a single-stranded molecule. While DNA contains deoxyribose, RNA contains ribose, characterised by the presence of the 2'-hydroxyl group on the pentose ring. This hydroxyl group make RNA less stable than DNA because it is more susceptible to hydrolysis. RNA contains the unmethylated form of the base thymine called uracil.

Biological evolution is the change in inherited traits over successive generations in populations of organisms. Adaptation is a key evolutionary process in which variation in the fitness of traits and species are adjusted by natural selection to become better suited for survival in specific ecological habitats. In evolutionary theory, adaptation is the biological mechanism by which organisms adjust to new environments or to changes in their current environment. This enables better survival and reproduction compared with other members of the species, leading to evolution.

Biogas can be transferred to the kitchen with the help of a digester through a tube. Biogas, when compared to other fuels, produces less pollution while cooking (with an exception of electric current). Furthermore, the byproducts of biogas can be used as fertilizer. Biogas also helps in producing indoor light.

Option c: Azotobacter is a freelivig bacteria which is present in the soil. They are aerobic and can survive only if there is presence of oxygen. It helps in fixing nitrogen by converting atmospheric nitrogen to ammonia. Thus, it is an example of non-symbiotic nitrogen fixing bacteria. Therefore, this is the correct option.

The anterior portion or top of the head is covered by a cap-like structure called an acrosome. This acrosome is filled with enzymes that help in getting in the ovum and cause fertilization. The head of the sperm mainly contains the nucleus. ... These help the sperm to break through the cell membrane of an egg.

Pollination is a biological process in which the pollen grains are transferred from an anther (male part of a flower) to the stigma (female part of a flower). There are two types of pollination:

• Self-Pollination
• Cross-Pollination

Aerenchyma is a modified parenchyma, where the cells are arranged with regular air spaces or air chambers to facilitate diffusion of gases to provide buoyancy to aquatic plants such as lotus and water hyacinth.

Two functions of hydrophytes are

(i) It helps in the diffusion of oxygen, both in and out.

(ii) It provides buoyancy to aquatic plants

Flowering in plants is a photoperiod-dependent process and accordingly, plants have been classified as long day and short day plants. In animals photoperiod affects the sexual behaviour and entry into the hibernation. 

Photoperiod refers to the duration of time per day that an organism is exposed to sunlight. In case of plants, germination, growth and flowering are dependent on  photoperiod.       

In many multi nucleated organisms, the cells divide and form multiple nuclei without the process of mitosis. Thus, multinucleated cells divide into similar daughter cells. The meaning of the word plasmotomy is something which is uncountable. It is a type of asexual reproduction. It is commonly found in protozoa. In protozoa, the parent organism divides into daughter organisms without the process of cell division. It is seen in Opalina and Plasmodium

Apomixis

Apomixis is a mechanism to produce seeds without fertilization. This mechanism produces clones, hence can be considered as a form of asexual reproduction.

Apomixis can occur in a number of ways, some of which are mentioned below:

Nucellar cells which are diploid & located outside the embryo sac continuously divide and enter inside embryo sac and later develop into embryos. In this way, multiple embryos can exist inside one ovule. This is termed as Polyembryony. It is seen commonly in Citrus, mango etc..

Sometimes, the egg cell is not formed as a result of reduction division, hence diploid. This diploid egg cell later directly develops into an embryo.

Some chromosomal conditions are caused by changes in the number of chromosomes. These changes are not inherited, but occur as random events during the formation of reproductive cells (eggs and sperm). An error in cell division called nondisjunction results in reproductive cells with an abnormal number of chromosomes. Some chromosomal abnormalities occur when there is an extra chromosome, while others occur when a section of a chromosome is deleted or duplicated. Examples of chromosomal abnormalities include Down syndrome, Trisomy 18, Trisomy 13, Klinefelter syndrome, XYY syndrome, Turner syndrome and triple X syndrome.

Hemiplegia is a condition caused by brain damage or spinal cord injury that leads to paralysis on one side of the body. It causes weakness, problems with muscle control, and muscle stiffness. The degree of hemiplegia symptoms vary depending on the location and extent of the injury. Hemiplegia affects just one side of your body and is usually caused by a stroke, which damages one side of your brain. Quadriplegia (or tetraplegia) is when all four limbs are paralyzed, sometimes along with certain organs. Paraplegia is paralysis from the waist down.

Anther is a four side structure consisting of four microsporangia located at each lobe. Each microsporangium consists of a unilayer of epidermal cells. Below epidermis, a layer of radially elongated cells called endothecium exists. Endothecium is followed by 2 or 3 middle layers of flattened and crushed parenchymatous cells. Below the middle layers is present tapetum, which is the innermost layer of microsporangium.