As in octahedral complex, [CoCl 3.3NH₃] doesn't form any ion so it is nonconducting.

But other complex give atleast one ion so they are conductor.

CoCl₃⋅4NH₃ gives two ion (one complex +one chloride).

CoCl₃.5NH₃ gives three ion (one complex + two chloride).

Hence, the correct option is (D).

The appendix or vermiform appendix is a muscular structure attached to the large intestine in the human body. It is a narrow tube resembling a worm and is named after the Latin word "vermiform" which means ‘worm-shaped’. The appendix extends from the lower end of the cecum, a pouch-like structure in the large intestine. The diameter of the appendix usually ranges from 7 to 8 mm and its length ranges between 2 and 20 cm, with an average length of 9 cm. The appendix is usually located at the lower right side of the abdomen.

Hence, the correct option is (D).

Protium is the most abundant isotope of hydrogen. The abundances of protium, deuterium and tritium are 99.984%,0.016% and 10⁻¹⁵% respectively.

Hence, the correct option is (C).

Antibiotics are compounds that are produced by an organism and inhibit the growth of another organism. They are mostly obtained from bacteria. They are used to fight the bacterial infection. However, they are not useful in viral infection. They act by either killing bacteria or preventing their reproduction. 

Hence, the correct option is (A).

An ecosystem is a natural unit that includes all organisms of a particular region, ie plants, animals, and molecules that interact with their abiotic environment to form a complete biological unit. Thus ecosystems are a unit of interdependent organisms that divide the same habitat. The ecosystem usually forms many food webs that show the interdependence of these organisms and the flow of energy within the ecosystem. In which they depend on each other for their food, food and other biological activities.  The keystone species in an ecosystem are those who are the main contributors to the ecosystem.

Hence, the correct option is (D).

Megaspore is the initial cell or beginning of the female gametophyte or embryo sac. The nucleus of the megaspore undergoes divisions and gives rise to the embryo sac or female gametophyte, which is called megagametogenesis. During development, the single nucleus of the functional megaspore (of the chalazal end) undergoes 3 mitotic divisions to form 8 nuclei. Out of these 8 nuclei, 4 are present at the micropylar end and 4 at chalazal end. One nucleus from each group comes in centre to form 2 polar nuclei. The remaining 3 nuclei at the micropylar end constitute egg apparatus and the remaining 3 nuclei at the chalazal end constitute 3 antipodal cells or antipodals. So it is 3 + 2 + 3 arrangement. So fully developed a normal type of female gametophyte or embryo sac is 8-nucleated and 7-celled structure.

Hence, the correct option is (D).

Size of planet is same as that of earth, it means volume of planet is same as volume of earth. 

So, the radius of planet = radius of earth = R (let)

Also we know, density = mass / volume

If volume is constant then density depends upon mass and it is directly proportional to mass.

According to question, density of planet is twice that of earth. 

∴ Mass of planet is twice that of earth. 

Let mass of earth is M 

Then mass of planet is 2M

Now, g = GM / R², for earth 

g′= G(2M) / R², for planet

Here you observed, 2g = g′ 

Hence, acceleration due to gravity on surface of planet is two times of acceleration due to gravity on earth's surface.

Acceleration due to gravity on planet's surface = 2 × 9.8 = 19.6 m/s²

Hence, the correct option is (A)

Interphase is the first growth stage after cell division. Three stages occur during interphase i.e. G 1, S, and G 2 stage wherein G 1 stage cells mature by making more cytoplasm and cell organelles. S phase is called the post-mitotic gap phase and during that phase, the cell synthesizes enzyme and energy needed for DNA duplication. It occurs between the G 1 and G 2 phases of the interphase. In the G 2 phase, all cell structures needed for cell division are made. Example: centriole.

Hence, the correct option is (B).