Leslie argues that an organism called a Euglena is a plant because it is eukaryotic, has a nucleus, makes its own food, and is unicellular. Where is Leslie's error?

Euglena lacks cell wall

Explanation:

Although euglena has many features of plant cells like

But it lacks cell wall which is a defining feature of plant cells. Instead of cell wall it has a pellicle which is made of protein and has a protective function for euglena. Thus it can not be clearly classified as a plant.

d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day

continuous conducting path for current, power supply