PTE

a sugary liquid produced by plants, often in flowers, that provides food for visiting animals

active mainly at night rather than during the day

the repeated movement and reuse of nutrients between living organisms and the nonliving parts of an ecosystem

the young produced by a parent organism or a pair of parents

an animal that eats both plant material and other animals

an individual living thing, such as a plant, animal, or bacterium

an organism that lives on or in another organism and obtains resources at that organism's expense

the process by which organisms convert light energy into chemical energy used to build organic substances

tiny grains produced by seed plants that carry the male reproductive cells or develop to produce them

to transfer pollen to the reproductive part of a flower, allowing fertilization to occur

the number of individuals in a population per unit of area or volume

an animal that hunts and eats other animals

animals that another animal hunts and eats

to free substances needed for growth so that other organisms can use them

the biological process by which new organisms are produced

an animal such as a snake, lizard, turtle, or crocodile, with scaly skin and body temperature strongly affected by its surroundings

not easily damaged or affected by a particular harmful substance, disease, or condition

all the roots of a plant considered as a connected structure for anchorage and absorption

a young plant that has recently developed from a seed

reproduction in which reproductive cells join, combining genetic material to produce offspring

a biological group whose organisms share a distinct evolutionary identity

defending a particular area against other animals, often to protect access to resources or mates

a group of cells organized together to carry out a particular function in an organism

to withstand an environmental condition without suffering serious damage or losing the ability to function

differences in characteristics among organisms within a population

the maximum amount of fish or other aquatic animals that may be caught within a defined area or period

farming whose main purpose is to produce crops or animal products for sale

decomposed organic material, such as plant remains, used to improve soil

to make water, soil, or another material impure or unsafe by introducing an unwanted substance