answer 2 A photocell is a device that converts light energy into electrical output.

From memory (?) selenium cells were the early photodetectors used on ancient photo equipment. (My Weston photo meter.)

It was not too difficult to improve on the selenium photocells.

Nowadays we are spoilt for choice for types of photocells, up to sophisticated photomltipliers, and solid state detectors that have completely replaced film for astronomy recording material.

M- move by flowing of cytoplasm over the surface i.e mud, soil.

- pseudopods - changing the shape of their body.

R-"breathes" using a porous cell membrane (oxygen in - carbon dioxide out)

S- no special sense organs.

- changes in outside world detected by all parts of living material

- limited sensitivity e.g. moves away from light, but it has no photodetectors or eyes

N- food is engulfed by pseudopods (False foot) - forms a food vacuole.

- eat algae, bacteria, other protozoans, tiny particles of dead plant / animal matter

E- ingestion and egestion can take place at any point on the surface

- no 'mouth' or 'anus'.

R- a parent cell divides (Nucleus + cytoplasm divide)

= two smaller daughter cells i.e. asexually by binary fission

G- grows from nutrition - digesting food.