Living things need the right physical conditions to grow and survive. Important conditions include light, water, temperature, air and nutrients in the soil.

Each living thing has a range of conditions it can survive in. If conditions are too extreme — too hot, too cold, too dry, too wet or too salty — it grows poorly or dies.

Animals are affected too. Many frogs need moist places so their skin does not dry out, and some animals hibernate or migrate to survive cold winters.

Investigation: How does the amount of water affect the growth of bean seedlings?

Five groups of three bean seedlings were grown in the same type of pot, with the same soil, on the same sunny windowsill. Each group was given a different amount of water every day. After 14 days the height of each seedling was measured.

Average height after 14 days

0 mL per day: 0 cm (seedlings died)

20 mL per day: 6 cm

40 mL per day: 11 cm

60 mL per day: heights 11 cm, 13 cm and 12 cm — average ?

80 mL per day: 7 cm (soil stayed soggy)