In Philadelphia's Franklin Institute, there is a working model of a human heart enough large for visitors to walk through.

• there is

• working model

• human heart

• enough large

The task of the cartographer is to represent the Earth's surface at a reduced greatly scale.

• task of

• is to

• Earth's surface

• reduced greatly

To grow well, a tree must be well-suited to the area where is it planted.

• grow well

• must be

• well-suited

• is it

The development of transistors made possible it to reduce the size of many electronic devices.

• development of

• possible it

• of many

• electronic devices

Twelve drawings usually have to be prepared for second each of animated film.

• usually have to

• prepared for

• second each

• animated film

Guess this food!

Today many garden vegetables have few resemblance to the wild plants from which they come

• garden vegetables

• few resemblance

• wild plants

• from which

Sloths are moving slow, shaggy mammals that are often seen hanging upside down from tree limbs.

• moving slow

• often seen

• upside down

• tree limbs

Carbohydrates as such sugar or starches are important energy sources for humans and animals.

• as such

• starches

• energy sources

• humans and animals

On nights when is the sky clear and the air calm, the Earth's surface rapidly radiates heat into the atmosphere

• is the sky

• air calm

• Earth's surface

• rapidly radiates