C.

Dilute solutions of boric acid and hydrogen, peroxide are strong antiseptics

Antiseptics and disinfectants both either kill or prevent the growth of microorganisms. The main point of difference between these two is that the former (antiseptics) are used for living beings whereas disinfectants are not safe for living tissues. These are actually used for inanimate objects like floors, tiles etc.
A substance like phenol in its lower concentration (0.2%) behaves as antiseptic whereas in higher concentration (1%) as disinfectant. Chlorine and iodine are strong disinfectants whereas dilute solutions of boric acid and hydrogen peroxide are mild antiseptics. 

C.

Aspartame

Aspartame is the only artificial sweetener which is stable at a lower temperature and decomposes at a higher temperature.

D.

antibiotic broad spectrum

a) Antifertility drugs are used to control pregnancy. These drugs prevent conception of fertilisation e.g., Mifepristone, norethindrone, mestranol etc. 
b) Antihistamines are used for the relief of allergies e.g., diphenhydramine, chlorpheniramine, promethazine etc.
c) Antiseptic is used to reduce the number and growth of microorganism e.g., Dettol soap etc, whereas disinfectants kill bacteria and are used for sterilisation of inanimate objects like instruments utensils clothes, floors etc. e.g., phenol, dental, iodol etc. 
d) Broad spectrum antibiotics are such antibiotics that act against a wide range of disease-causing bacteria. They act against both Gram-positive and Gram -negative bacteria. e.g, ampicillin chloramphenicol etc. 

B.

Antiseptic

The mixture of chloroxylenol and terpineol acts as antiseptic.

D.

Thyroxine

Thyroxine is 3,5,3', 5'- tetraiodothyronine. It is secreted by follicular cells of thyroid glands. Its structure is as 


Thyroxine stimulates the consumption of oxygen and thus, the metabolism of all cells or tissue in the body.