When someone claims to be children of someone, inheritance pattern can be used to prove whether it is possible or not. Dominant trait (like cleft chin) will always be expressed so it cannot appear from a parent without the trait.
If the father and mother don't have a cleft chin, it would be impossible to have a child with a cleft chin. That way, the claim can be considered as impossible/false.
Glucagon and insulin have antagonistic effects, with glucagon promoting glucose production and release into the bloodstream, and insulin promoting the transport of glucose into cells from the bloodstream and inhibiting glucose production. In which way this two component work together to make sure your still at homeostasis.
Answer:
Without the primary consumers there would be no source of energy for carnivores or secondary consumers so no secondary consumers would exist in that ecosystem. Also there would by definition be no primary consumers. The producers would be the only organisms in the ecosystem, besides decomposers.