Explanation

Gram-positive bacteria have a thick layer of peptidoglycan but lack the outer membrane containing lipopolysaccharides, which is characteristic of Gram-negative bacteria. 

Additional information:

Peptidoglycan: Gram-positive bacteria are defined by their thick layer of peptidoglycan. 

Cell wall: Gram-positive bacteria possess a cell wall composed primarily of peptidoglycan. 

Capsule: While not a defining feature of Gram-positivity, some Gram-positive bacteria can have a capsule.

Explanation

Prostaglandins are released by the breakdown of fatty acids.

Specifically, they are produced from the fatty acid arachidonic acid through a series of enzymatic steps involving cyclooxygenase (COX) enzymes. 

Explanation

The best description of an exothermic reaction is that it releases heat into the surroundings.

This causes the temperature of the surroundings to increase.

Key characteristics of exothermic reactions:

Releases heat:

The word "exo" means "out" and "thermic" means "heat," so the energy exits the system

Energy change:

The products of the reaction have less chemical potential energy than the reactants.

The energy difference is released into the surroundings, often as heat.

Negative enthalpy change:

In thermochemistry, this is represented by a negative change in enthalpy (Delta H<0).

Examples: Common examples include burning a substance, rusting iron, and the reaction that occurs inside hand warmers. 

Explanation

The Radius is a bone found in the arm. 

Femur: The femur, or thigh bone, is the longest and strongest bone in the body and is located in the leg.

Semum: This is not a bone in the human body. The word may be a typo for another term.

Patella: The patella, also known as the kneecap, is the bone located in front of the knee joint. 

Explanation

Sunbathing is primarily a good source of vitamin D

When UVB rays from the sun hit the skin, they convert a substance called 7-dehydrocholesterol into vitamin D3. 

This vitamin D3 then travels to the liver and kidneys to become the active form of vitamin D, which the body uses to absorb calcium and phosphorus. 

Benefits of Sunlight

Bone Health:

Vitamin D helps your body absorb calcium and phosphorus, which are crucial for strong bones. 

Immune System:

Adequate vitamin D levels are linked to a stronger immune system and may help regulate immune responses.