a tiny particle of light or electromagnetic radiation

(a)  

capable of being slowly destroyed and broken down into very small parts by natural processes, bacteria, etc

(a)  

a wealthy person who gives money and time to help make life better for other people

(a)  

a science that deals with things that are alive, such as plants and animals; the study of life

(a)  

the process by which a green plant turns water and carbon dioxide into food when the plant is exposed to light

(a)  

the art, process, or job of taking pictures with a camera; name after the original process that used light to expose an image on special paper

(a)  

the study of ideas about knowledge, truth, the nature and meaning of life; your personal beliefs or opinions related to life

(a)  

the story of a real person's life written by someone other than that person

(a)  

a US city founded by William Penn, a Quaker who believed in peace

(a)  

It's pretty evident from my huge library that I am a (a)  

(a)   within a plant can only occur in the presence of light.

I have learned so much about living things in my (a)   class.

The literal translation of (a)   is the "city of brotherly love".

Most paper goods are (a)   and can be broken down by living things called decomposers.

My (a)   is that you must always treat others with love and respect.

Before digital cameras, (a)   required artists to develop their prints in dark rooms that prevented light from ruining their pictures.

All light is made up of photons, which are so small that you cannot see them individually.

(a)  

I will write a (a)   about Abraham Lincoln because I know so many fascinating things about his life.

Steven was a (a)   who cared deeply about homeless children; he held many fundraisers and donated a lot of money to help them.