You are observing a blood slide under the microscope and you see a large cell with a U-shaped nucleus and light blue cytoplasm. You identify this cell as a .

Monocytes.

Explanation:

Monocytes have a abundant amount of gray cytoplasm with fine lilac granules in it and because of this the cytoplasm appears ground glass.

The vacuoles are vacant and there is a gap sen in the cell as vacuoles when observed under microscope. The vacuoles of the monocytes are not stained.

They have a U-shaped nucleus and are extremely motile. The monocytes are lightly stained as compared to leukocytes.

"do a testcross with a homozygous recessive plant."

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.