Questions

Japan's - Japan Aerospace Exploration Agency (JAXA) has successfully launched the world's smallest rocket with the ability to put a tiny satellite into orbit. Rocket -  SS-520 which was pnce failed in 2017 lifted off from the Space Center carrying a microsatellite TRICOM-1R, a three-unit CubeSat weighing about 3 kilograms. The CubeSat will now be used to collect images of the Earth's surface via multiple cameras.

Sodium chloride:

The solubility rules tell you that all halides are soluble with the exception of those formed with siver, mercury, and lead ions. Since this is not the case here, sodium chloride will be soluble.

Silver nitrate:

It is soluble because all nitrates are soluble, without exception.

Potassium sulfate:

It is soluble because all sulfates are soluble with the exception of those formed with silver, calcium, barium, mercury, lead, and strontium ions.

Copper (II) hydroxyde:

It is insoluble because all hydroxides are insoluble with the exception of those formed with alkali metal ions and barium.

Glands are of two types. The exocrine glands have ducts to carry their secretions and these secretions contain enzymes. on the other hand, endocrine glands are ductless glands and they secrete mainly horomones.

23 chromosomes are in a human gamete.

Human somatic cells have 46 chromosomes(23 pairs) but a gamete(germ cell) gets half the amount, i.e. 23 chromosomes, (one from each pair). There will be half the number of chromosomes an organism has in its somatic cells (all other body cells except gametes).

For example in humans, the somatic cells contain 46 chromosomes which are the diploid number (2n) and each sperm and egg has 23 chromosomes where one of them is the sex chromosome.

Dull means not sharp, not shining, not bright, ...

Hence, the given words are all that means the opposite of dull.