The signs used depend on the species being surveyed and include the presence of runways and tracks on * 1 point
(a). soft substrates
(b) hard substrate
(c) dry mud
(d) rocks

(a). soft substrates

Explanation:

Mobile organisms can be measured by both direct and indirect methods. Direct methods may involve observing the actual behavior (e.g., scoring via timing). Moreover, indirect methods are those where the technique used depends on the species being examined, collecting information such as through recording of tracks in the soft substrate (e.g., mud, sand, snow), presence of fur/feathers, droppings (mammals), etc. For example, indirect observation of insects may involve the determination of exoskeletons, sounds, etc.

water is a polar molecule. a chemical bond is a force of attraction between atoms or ions. bonds form when atoms share or transfer valence electrons. atoms form chemical bonds to achieve a full outer energy level, which is the most stable arrangement of electrons. so, false

explanation:

in h2o molecule, two water molecules are bonded by a hydrogen bond but the bond between two h - o bonds within a water molecule are covalent. the greater the electronegativity difference, the more ionic the bond is. bonds that are partly ionic are called polar covalent bonds. nonpolar covalent bonds, with equal sharing of the bond electrons, arise when the electronegativities of the two atoms are equal.

your body is trying to warm itself up. or more precisely, sensors in your skin send messages to your brain to generate heat to your body.