The main reason for sweating in mammals is to A. regulates excess water in the body B. reduce salt in the body C. control the body temperature D. control urea in the body

Sweating is a physiological process primarily used by mammals to regulate their body temperature. As sweat evaporates from the skin, it carries away heat, thus cooling the body.
The correct option is C.

$$\boxed{\text{C}}$$

Insects possess an exoskeleton, which is a hard, external covering that provides support and protection.
The correct option is B.

$$\boxed{\text{B}}$$

Oil and water are immiscible liquids that separate into layers due to their different densities. Decantation is the process of separating mixtures by pouring off the top layer, which is suitable for separating oil from water.
The correct option is B.

$$\boxed{\text{B}}$$

The oval window is a membrane-covered opening that leads from the middle ear to the vestibule of the inner ear. It is crucial for the transmission of sound vibrations.
The correct option is D.

$$\boxed{\text{D}}$$

Birds have hollow bones (pneumatized bones) which are lightweight yet strong, significantly reducing their overall body mass and aiding in flight.
The correct option is C.

$$\boxed{\text{C}}$$

In flowering plants, the male reproductive cells (gametes) are contained within pollen grains, which are produced in the anthers.
The correct option is D.

$$\boxed{\text{D}}$$

Insects breathe through a system of tubes called trachea (or tracheae), which open to the outside through small pores called spiracles. This system delivers oxygen directly to the tissues.
The correct option is D.

$$\boxed{\text{D}}$$

The standard taxonomic hierarchy is: Kingdom, Phylum, Class, Order, Family, Genus, Species. Therefore, Phylum is the largest rank after Kingdom.
The correct option is C.

$$\boxed{\text{C}}$$

An ecosystem is a complete ecological unit that includes all the living organisms (biotic components) in an area interacting with each other and with their non-living physical environment (abiotic components).
The correct option is D.

$$\boxed{\text{D}}$$

Non-communicable diseases (NCDs) are not spread from person to person. Asthma, Cancer, and Diabetes are NCDs. Gonorrhea is a sexually transmitted infection caused by bacteria, making it a communicable disease.
The correct option is D.

$$\boxed{\text{D}}$$

Question 11: (The question is partially obscured, but based on the options, it likely asks about factors that are not beneficial for health or are harmful, with one option being an exception.) ...all the following except...
Assuming the question asks for something generally harmful, and one option is beneficial:
A. drinking and smoking (Harmful)
B. having adequate sleep (Beneficial)
If the question is "All the following are harmful to health except...", then "having adequate sleep" is the exception.
The correct option is B.

$$\boxed{\text{B}}$$

While all areas of the tongue can detect all tastes to some extent, the tip of the tongue is generally most sensitive to sweet tastes.
The correct option is A.

$$\boxed{\text{A}}$$

Amoeba reproduces asexually, typically through binary fission, which does not involve mating. Toads, pigs, and lions reproduce sexually.
The correct option is D.

$$\boxed{\text{D}}$$

In a second-class lever, the load is located between the fulcrum and the effort. A wheelbarrow is a classic example: the wheel is the fulcrum, the load is in the middle, and the effort is applied at the handles.
The correct option is A.

$$\boxed{\text{A}}$$

A process that releases heat energy is exothermic.

• A. Gas to liquid (Condensation) - Exothermic, heat is released.
• B. Liquid to gas (Evaporation) - Endothermic, heat is absorbed.
• C. Solid to gas (Sublimation) - Endothermic, heat is absorbed.
• D. Solid to liquid (Melting) - Endothermic, heat is absorbed. The correct option is A.

$$\boxed{\text{A}}$$

The fundamental building block of an element is an atom. However, among the given options, the proton is the subatomic particle that defines an element's identity (its atomic number).
The correct option is D.

$$\boxed{\text{D}}$$

The atomic number of an element is defined solely by the number of protons in the nucleus of an atom of that element.
The correct option is A.

$$\boxed{\text{A}}$$

Water is a polar solvent, meaning it can dissolve other polar substances and ionic compounds. Salt (e.g., sodium chloride, NaCl) is an ionic compound that readily dissolves in water. Butter, kerosene, and sand are generally non-polar or insoluble in water.
The correct option is D.

$$\boxed{\text{D}}$$

Elements in Group VII (also known as Group 17 or halogens) of the periodic table are characterized by having 7 valence electrons in their outermost electron shell.
The correct option is D.

$$\boxed{\text{D}}$$

A physical change alters the form or appearance of a substance but does not change its chemical composition.

• A. Burning of paper into ash (Chemical change)
• B. Digestion of starch (Chemical change)
• C. Melting of ice (Physical change - water changes from solid to liquid, but remains H₂O)
• D. Rusting of iron (Chemical change) The correct option is C.

$$\boxed{\text{C}}$$

The maximum number of electrons that can occupy an electron shell is given by the formula $2n^2$, where $n$ is the shell number. For the second shell ($n=2$):

$$2 \times (2)^2 = 2 \times 4 = 8$$

The second shell can hold a maximum of 8 electrons.
The correct option is B.

$$\boxed{\text{B}}$$

Rusting is the common term for the corrosion of iron and its alloys. It is an electrochemical process that requires both oxygen (from air) and water (moisture) to occur.
The correct option is C.

$$\boxed{\text{C}}$$

After being filtered and processed by the nephrons in the renal cortex and medulla, urine collects in the renal pelvis, which is a funnel-shaped structure in the center of the kidney, before it flows into the ureter.
The correct option is C.

$$\boxed{\text{C}}$$