Answer: Option C.
The number of protons and neurons it's contain.
Explanation:
Mass number of an atom is also called atomic mass of an atom which is some what expressed in Dalton i.e 1/2. The mass number is the total number of protons and neutrons altogether called nucleons in an atomic nucleus.
Answer:
The enzyme responsible for separating the two strands of DNA in a helix so that they can be copied during DNA replication.Explanation:
Answer :— Physical properties of plastic samples collected by SEA in the Atlantic Ocean indicate the collected material is made of HDPE (high density polyethylene), LDPE (low density polyethylene), and PP (polypropylene), which are used to make common household items such as milk jugs, plastic bags, and drinking straws.Plastics and polystyrene foam (Styrofoam) comprise 90% of all marine debris, with single-use food and beverage containers being one of the most common items found in ocean and coastal surveys.

Hope you understand
Trophic levels go by,
Producer (The nuts)
Primary Consumer (Squirrels)
Secondary Consumer (Raccoons)
Tertiary Consumer (Bear)
So squirrels would be at a lower trophic level.
Hope his help :)
Answer:
Thylakoids, stroma
Explanation:
The interconnected flattened sacs within the inner membrane of the chloroplast are called thylakoid. Many thylakoids are come together and get arranges in a stack called a granum.
Thylakoid contains chlorophyll pigment and is responsible for absorbing the sunlight and conducting light reaction. These thylakoids or grana are suspended in a liquid called the stroma.
The stroma contains the enzymes which are required in the light-dependent reaction. It contains DNA, ribosome, starch. The synthesis of organic molecules occurs in the stroma.