Answer: The correct answer is black because the product of its side and mass is lower.
Explanation: Density of a substance is defined as the mount of matter that can be stored in a given volume.
Mathematically,

As, density is inversely proportional to the volume of the substance.
The substance will be more denser if it has less volume and it will be less denser if the volume is more.
We are given two cubes having different sides.
Volume of the cube is calculated by using the formula:

where, a = side of the cube.
Black: The side of this cube is 2 and volume will be =
Yellow: The side of this cube is 3 and volume will be =
As, the volume of black cube is less. So, this cube will be more denser.
Density of black cube: 
Density of Yellow Cube: 
Hence, black cube will be more denser because the product of its side and mass is lower.
Compressibility is a chemical property because it’s made more compact
The correct answer is (a).
Both L-D and L-IND reactions take place in the chloroplast of the cell but in different parts or locations. L-D reactions take place in the chloroplast thylakoids while L-IND reactions take place in the chloroplast stroma.
Chloroplasts are chlorophyll- filled organelles mostly found in the leaves of green plants. Chloroplasts are surrounded by a double membrane called the thykaloid membrane that forms long folds within the organelle. In electron micrographs, the thykaloid membranes look like stacked coins. Chlorophyll is located within the thykaloid membranes.
Between the thykaloid membrane and the chloroplast membrane is a space. This space is what is called the stroma.
Red blood cell is shaped as a biconcave discs, this shape allows them to squeeze through small capillaries.
The biconcave shape of the cell allows oxygen exchange at a constant rate over the largest possible area. The biconcave shape increases the cell's surface area compared to a flat disk of the same size. The greater surface area makes it easier for gases to move into and out of the red blood cell.
The biconcave shape provides a large surface area compared to the volume of the red blood cell, allowing diffusion to happen efficiently. This shape optimizes the ratio of surface area to volume, facilitating gas exchange. It also enables them to fold up as they move through narrow blood vessels.
To learn more about biconcave discs ,here
brainly.com/question/8193368
#SPJ4